K8s emptyDir on virtio-fs provisioned on memory filesystem

[awprice]

Description of problem

When using virtio-fs for the shared_fs, Kubernetes emptyDirs are being provisioned on a memory based filesystem. This is incorrect, as emptyDir should be on a disk.

I believe this is due to the changes made in #1485, where the emptyDir is provisioned on the file system of the sandbox container. This worked fine when using 9p or devicemapper for rootfs, but when using virtio-fs, the rootfs of the sandbox container is being provisioned on a memory filesystem.

Note: we are NOT referring to emptyDir medium: Memory, but the default medium for emptyDir.

Expected result

emptyDir to be provisioned with virtio-fs and to have the same performance as the rootfs of of the non-sandbox containers.

Actual result

emptyDir is being provisioned in the sandbox container's filesystem, which is memory backed. Thus, the IO performance of emptyDir, is the same as a emptyDir with medium: Memory.

Just to prove that the emptyDir is being provisioned on memory, I ran the following command in an emptyDir - sync; dd if=/dev/zero of=./tempfile bs=1M count=102400; sync, which will create a 100GB file.

We can then see the tmpfs for /run now has a 100GB file in it:

df -h | grep /run
Filesystem       Size  Used Avail Use% Mounted on
tmpfs            252G  101G  152G  40% /run

Other stuff

The pod I am using to test this:

apiVersion: v1
kind: Pod
metadata:
  name: test
  namespace: default
  annotations:
    io.kubernetes.cri.untrusted-workload: "true"
spec:
  containers:
    - name: sleep
      image: ubuntu
      command:
        - sleep
        - "3600"
      volumeMounts:
        - mountPath: /host-emptydir
          name: host-emptydir
        - mountPath: /memory-emptydir
          name: memory-emptydir
  volumes:
    - name: host-emptydir
    - name: memory-emptydir
      emptyDir:
        medium: "Memory"

Show kata-collect-data.sh details

Meta details

Running kata-collect-data.sh version 1.8.0-alpha1 (commit 7aaf61d44d1e79e792af707387bbbc7e809e98c2) at 2019-06-21.06:50:14.771979354+0000.

---

Runtime is /opt/kata/bin/kata-runtime.

kata-env

Output of "/opt/kata/bin/kata-runtime kata-env":

[Meta]
  Version = "1.0.23"

[Runtime]
  Debug = false
  Trace = false
  DisableGuestSeccomp = true
  DisableNewNetNs = false
  Path = "/opt/kata/bin/kata-runtime"
  [Runtime.Version]
    Semver = "1.8.0-alpha1"
    Commit = "7aaf61d44d1e79e792af707387bbbc7e809e98c2"
    OCI = "1.0.1-dev"
  [Runtime.Config]
    Path = "/etc/kata-containers/configuration.toml"

[Hypervisor]
  MachineType = "virt"
  Version = "NEMU (like QEMU) version 4.0.0 (kata-static)\nCopyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers"
  Path = "/opt/kata/bin/nemu-system-x86_64"
  BlockDeviceDriver = "virtio-scsi"
  EntropySource = "/dev/urandom"
  Msize9p = 8192
  MemorySlots = 10
  Debug = false
  UseVSock = false
  SharedFS = "virtio-fs"

[Image]
  Path = "/opt/kata/share/kata-containers/kata-containers-ubuntu-console.img"

[Kernel]
  Path = "/opt/kata/share/kata-containers/vmlinuz-4.19.28-41"
  Parameters = "init=/usr/lib/systemd/systemd systemd.unit=kata-containers.target systemd.mask=systemd-networkd.service systemd.mask=systemd-networkd.socket"

[Initrd]
  Path = ""

[Proxy]
  Type = "kataProxy"
  Version = "kata-proxy version 1.8.0-alpha1-d1dc8639bc30b099ee560afbf971e61dd7ce3b2f"
  Path = "/opt/kata/libexec/kata-containers/kata-proxy"
  Debug = false

[Shim]
  Type = "kataShim"
  Version = "kata-shim version 1.8.0-alpha1-9ac42424de1748ddaabff8bc744e6313ddaec3f2"
  Path = "/opt/kata/libexec/kata-containers/kata-shim"
  Debug = false

[Agent]
  Type = "kata"
  Debug = false
  Trace = false
  TraceMode = ""
  TraceType = ""

[Host]
  Kernel = "4.19.43-coreos"
  Architecture = "amd64"
  VMContainerCapable = true
  SupportVSocks = true
  [Host.Distro]
    Name = "Container Linux by CoreOS"
    Version = "2079.4.0"
  [Host.CPU]
    Vendor = "GenuineIntel"
    Model = "Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz"

[Netmon]
  Version = "kata-netmon version 1.8.0-alpha1"
  Path = "/opt/kata/libexec/kata-containers/kata-netmon"
  Debug = false
  Enable = false

---

Runtime config files

Runtime default config files

/etc/kata-containers/configuration.toml
/opt/kata/share/defaults/kata-containers/configuration.toml

Runtime config file contents

Output of "cat "/etc/kata-containers/configuration.toml"":

# Copyright (c) 2019 Intel Corporation
#
# SPDX-License-Identifier: Apache-2.0
#

# XXX: WARNING: this file is auto-generated.
# XXX:
# XXX: Source file: "cli/config/configuration-nemu.toml.in"
# XXX: Project:
# XXX:   Name: Kata Containers
# XXX:   Type: kata

# nemu utilizes the 'qemu' hypervisor template type, since it closely matches qemu
[hypervisor.qemu]
path = "/opt/kata/bin/nemu-system-x86_64"
kernel = "/opt/kata/share/kata-containers/vmlinuz.container"
image = "/opt/kata/share/kata-containers/kata-containers.img"
machine_type = "virt"

# Optional space-separated list of options to pass to the guest kernel.
# For example, use `kernel_params = "vsyscall=emulate"` if you are having
# trouble running pre-2.15 glibc.
#
# WARNING: - any parameter specified here will take priority over the default
# parameter value of the same name used to start the virtual machine.
# Do not set values here unless you understand the impact of doing so as you
# may stop the virtual machine from booting.
# To see the list of default parameters, enable hypervisor debug, create a
# container and look for 'default-kernel-parameters' log entries.
kernel_params = ""

# Path to the firmware.
# If you want that qemu uses the default firmware leave this option empty
firmware = "/opt/kata/share/kata-nemu/OVMF.fd"

# Machine accelerators
# comma-separated list of machine accelerators to pass to the hypervisor.
# For example, `machine_accelerators = "nosmm,nosmbus,nosata,nopit,static-prt,nofw"`
machine_accelerators=""

# Default number of vCPUs per SB/VM:
# unspecified or 0                --> will be set to 1
# < 0                             --> will be set to the actual number of physical cores
# > 0 <= number of physical cores --> will be set to the specified number
# > number of physical cores      --> will be set to the actual number of physical cores
default_vcpus = 1

# Default maximum number of vCPUs per SB/VM:
# unspecified or == 0             --> will be set to the actual number of physical cores or to the maximum number
#                                     of vCPUs supported by KVM if that number is exceeded
# > 0 <= number of physical cores --> will be set to the specified number
# > number of physical cores      --> will be set to the actual number of physical cores or to the maximum number
#                                     of vCPUs supported by KVM if that number is exceeded
# WARNING: Depending of the architecture, the maximum number of vCPUs supported by KVM is used when
# the actual number of physical cores is greater than it.
# WARNING: Be aware that this value impacts the virtual machine's memory footprint and CPU
# the hotplug functionality. For example, `default_maxvcpus = 240` specifies that until 240 vCPUs
# can be added to a SB/VM, but the memory footprint will be big. Another example, with
# `default_maxvcpus = 8` the memory footprint will be small, but 8 will be the maximum number of
# vCPUs supported by the SB/VM. In general, we recommend that you do not edit this variable,
# unless you know what are you doing.
default_maxvcpus = 0

# Bridges can be used to hot plug devices.
# Limitations:
# * Currently only pci bridges are supported
# * Until 30 devices per bridge can be hot plugged.
# * Until 5 PCI bridges can be cold plugged per VM.
#   This limitation could be a bug in the kernel
# Default number of bridges per SB/VM:
# unspecified or 0   --> will be set to 1
# > 1 <= 5           --> will be set to the specified number
# > 5                --> will be set to 5
default_bridges = 1

# Default memory size in MiB for SB/VM.
# If unspecified then it will be set 2048 MiB.
default_memory = 2048
#
# Default memory slots per SB/VM.
# If unspecified then it will be set 10.
# This is will determine the times that memory will be hotadded to sandbox/VM.
#memory_slots = 10

# The size in MiB will be plused to max memory of hypervisor.
# It is the memory address space for the NVDIMM devie.
# If set block storage driver (block_device_driver) to "nvdimm",
# should set memory_offset to the size of block device.
# Default 0
#memory_offset = 0

# Disable block device from being used for a container's rootfs.
# In case of a storage driver like devicemapper where a container's 
# root file system is backed by a block device, the block device is passed
# directly to the hypervisor for performance reasons. 
# This flag prevents the block device from being passed to the hypervisor, 
# 9pfs is used instead to pass the rootfs.
disable_block_device_use = false

# Shared file system type:
#   - virtio-fs (default)
#   - virtio-9p
shared_fs = "virtio-fs"

# Path to vhost-user-fs daemon.
virtio_fs_daemon = "/opt/kata/bin/virtiofsd-x86_64"

# Default size of DAX cache in MiB
virtio_fs_cache_size = 1024

# Cache mode:
#
#  - none
#    Metadata, data, and pathname lookup are not cached in guest. They are
#    always fetched from host and any changes are immediately pushed to host.
#
#  - auto
#    Metadata and pathname lookup cache expires after a configured amount of
#    time (default is 1 second). Data is cached while the file is open (close
#    to open consistency).
#
#  - always
#    Metadata, data, and pathname lookup are cached in guest and never expire.
virtio_fs_cache = "always"

# Block storage driver to be used for the hypervisor in case the container
# rootfs is backed by a block device. This is virtio-scsi, virtio-blk
# or nvdimm.
block_device_driver = "virtio-scsi"

# Specifies cache-related options will be set to block devices or not.
# Default false
#block_device_cache_set = true

# Specifies cache-related options for block devices.
# Denotes whether use of O_DIRECT (bypass the host page cache) is enabled.
# Default false
#block_device_cache_direct = true

# Specifies cache-related options for block devices.
# Denotes whether flush requests for the device are ignored.
# Default false
#block_device_cache_noflush = true

# Enable iothreads (data-plane) to be used. This causes IO to be
# handled in a separate IO thread. This is currently only implemented
# for SCSI.
#
enable_iothreads = false

# Enable pre allocation of VM RAM, default false
# Enabling this will result in lower container density
# as all of the memory will be allocated and locked
# This is useful when you want to reserve all the memory
# upfront or in the cases where you want memory latencies
# to be very predictable
# Default false
#enable_mem_prealloc = true

# Enable huge pages for VM RAM, default false
# Enabling this will result in the VM memory
# being allocated using huge pages.
# This is useful when you want to use vhost-user network
# stacks within the container. This will automatically 
# result in memory pre allocation
enable_hugepages = false

# Enable swap of vm memory. Default false.
# The behaviour is undefined if mem_prealloc is also set to true
#enable_swap = true

# This option changes the default hypervisor and kernel parameters
# to enable debug output where available. This extra output is added
# to the proxy logs, but only when proxy debug is also enabled.
# 
# Default false
#enable_debug = true

# Disable the customizations done in the runtime when it detects
# that it is running on top a VMM. This will result in the runtime
# behaving as it would when running on bare metal.
# 
#disable_nesting_checks = true

# This is the msize used for 9p shares. It is the number of bytes 
# used for 9p packet payload.
#msize_9p = 8192

# If true and vsocks are supported, use vsocks to communicate directly
# with the agent (no proxy is started).
# Default true
#use_vsock = true

# VFIO devices are hotplugged on a bridge by default. 
# Enable hotplugging on root bus. This may be required for devices with
# a large PCI bar, as this is a current limitation with hotplugging on 
# a bridge. This value is valid for "pc" machine type.
# Default false
#hotplug_vfio_on_root_bus = true

# If host doesn't support vhost_net, set to true. Thus we won't create vhost fds for nics.
# Default false
#disable_vhost_net = true
#
# Default entropy source.
# The path to a host source of entropy (including a real hardware RNG)
# /dev/urandom and /dev/random are two main options.
# Be aware that /dev/random is a blocking source of entropy.  If the host
# runs out of entropy, the VMs boot time will increase leading to get startup
# timeouts.
# The source of entropy /dev/urandom is non-blocking and provides a
# generally acceptable source of entropy. It should work well for pretty much
# all practical purposes.
#entropy_source= "/dev/urandom"

# Path to OCI hook binaries in the *guest rootfs*.
# This does not affect host-side hooks which must instead be added to
# the OCI spec passed to the runtime.
#
# You can create a rootfs with hooks by customizing the osbuilder scripts:
# https://github.com/kata-containers/osbuilder
#
# Hooks must be stored in a subdirectory of guest_hook_path according to their
# hook type, i.e. "guest_hook_path/{prestart,postart,poststop}".
# The agent will scan these directories for executable files and add them, in
# lexicographical order, to the lifecycle of the guest container.
# Hooks are executed in the runtime namespace of the guest. See the official documentation:
# https://github.com/opencontainers/runtime-spec/blob/v1.0.1/config.md#posix-platform-hooks
# Warnings will be logged if any error is encountered will scanning for hooks,
# but it will not abort container execution.
#guest_hook_path = "/usr/share/oci/hooks"

[factory]
# VM templating support. Once enabled, new VMs are created from template
# using vm cloning. They will share the same initial kernel, initramfs and
# agent memory by mapping it readonly. It helps speeding up new container
# creation and saves a lot of memory if there are many kata containers running
# on the same host.
#
# When disabled, new VMs are created from scratch.
#
# Note: Requires "initrd=" to be set ("image=" is not supported).
#
# Default false
#enable_template = true

# Specifies the path of template.
#
# Default "/run/vc/vm/template"
#template_path = "/run/vc/vm/template"

# The number of caches of VMCache:
# unspecified or == 0   --> VMCache is disabled
# > 0                   --> will be set to the specified number
#
# VMCache is a function that creates VMs as caches before using it.
# It helps speed up new container creation.
# The function consists of a server and some clients communicating
# through Unix socket.  The protocol is gRPC in protocols/cache/cache.proto.
# The VMCache server will create some VMs and cache them by factory cache.
# It will convert the VM to gRPC format and transport it when gets
# requestion from clients.
# Factory grpccache is the VMCache client.  It will request gRPC format
# VM and convert it back to a VM.  If VMCache function is enabled,
# kata-runtime will request VM from factory grpccache when it creates
# a new sandbox.
#
# Default 0
#vm_cache_number = 0

# Specify the address of the Unix socket that is used by VMCache.
#
# Default /var/run/kata-containers/cache.sock
#vm_cache_endpoint = "/var/run/kata-containers/cache.sock"

[proxy.kata]
path = "/opt/kata/libexec/kata-containers/kata-proxy"

# If enabled, proxy messages will be sent to the system log
# (default: disabled)
#enable_debug = true

[shim.kata]
path = "/opt/kata/libexec/kata-containers/kata-shim"

# If enabled, shim messages will be sent to the system log
# (default: disabled)
#enable_debug = true

# If enabled, the shim will create opentracing.io traces and spans.
# (See https://www.jaegertracing.io/docs/getting-started).
#
# Note: By default, the shim runs in a separate network namespace. Therefore,
# to allow it to send trace details to the Jaeger agent running on the host,
# it is necessary to set 'disable_new_netns=true' so that it runs in the host
# network namespace.
#
# (default: disabled)
#enable_tracing = true

[agent.kata]
# If enabled, make the agent display debug-level messages.
# (default: disabled)
#enable_debug = true

# Enable agent tracing.
#
# If enabled, the default trace mode is "dynamic" and the
# default trace type is "isolated". The trace mode and type are set
# explicity with the `trace_type=` and `trace_mode=` options.
#
# Notes:
#
# - Tracing is ONLY enabled when `enable_tracing` is set: explicitly
#   setting `trace_mode=` and/or `trace_type=` without setting `enable_tracing`
#   will NOT activate agent tracing.
#
# - See https://github.com/kata-containers/agent/blob/master/TRACING.md for
#   full details.
#
# (default: disabled)
#enable_tracing = true
#
#trace_mode = "dynamic"
#trace_type = "isolated"

[netmon]
# If enabled, the network monitoring process gets started when the
# sandbox is created. This allows for the detection of some additional
# network being added to the existing network namespace, after the
# sandbox has been created.
# (default: disabled)
#enable_netmon = true

# Specify the path to the netmon binary.
path = "/opt/kata/libexec/kata-containers/kata-netmon"

# If enabled, netmon messages will be sent to the system log
# (default: disabled)
#enable_debug = true

[runtime]
# If enabled, the runtime will log additional debug messages to the
# system log
# (default: disabled)
#enable_debug = true
#
# Internetworking model
# Determines how the VM should be connected to the
# the container network interface
# Options:
#
#   - bridged
#     Uses a linux bridge to interconnect the container interface to
#     the VM. Works for most cases except macvlan and ipvlan.
#
#   - macvtap
#     Used when the Container network interface can be bridged using
#     macvtap.
#
#   - none
#     Used when customize network. Only creates a tap device. No veth pair.
#
#   - tcfilter
#     Uses tc filter rules to redirect traffic from the network interface
#     provided by plugin to a tap interface connected to the VM.
#
internetworking_model="tcfilter"

# disable guest seccomp
# Determines whether container seccomp profiles are passed to the virtual
# machine and applied by the kata agent. If set to true, seccomp is not applied
# within the guest
# (default: true)
disable_guest_seccomp=true

# If enabled, the runtime will create opentracing.io traces and spans.
# (See https://www.jaegertracing.io/docs/getting-started).
# (default: disabled)
#enable_tracing = true

# If enabled, the runtime will not create a network namespace for shim and hypervisor processes.
# This option may have some potential impacts to your host. It should only be used when you know what you're doing.
# `disable_new_netns` conflicts with `enable_netmon`
# `disable_new_netns` conflicts with `internetworking_model=bridged` and `internetworking_model=macvtap`. It works only
# with `internetworking_model=none`. The tap device will be in the host network namespace and can connect to a bridge
# (like OVS) directly.
# If you are using docker, `disable_new_netns` only works with `docker run --net=none`
# (default: false)
#disable_new_netns = true

# Enabled experimental feature list, format: ["a", "b"].
# Experimental features are features not stable enough for production,
# They may break compatibility, and are prepared for a big version bump.
# Supported experimental features:
# 1. "newstore": new persist storage driver which breaks backward compatibility,
#				expected to move out of experimental in 2.0.0.
# (default: [])
experimental=[]

Output of "cat "/opt/kata/share/defaults/kata-containers/configuration.toml"":

# Copyright (c) 2017-2019 Intel Corporation
#
# SPDX-License-Identifier: Apache-2.0
#

# XXX: WARNING: this file is auto-generated.
# XXX:
# XXX: Source file: "cli/config/configuration-qemu.toml.in"
# XXX: Project:
# XXX:   Name: Kata Containers
# XXX:   Type: kata

[hypervisor.qemu]
path = "/opt/kata/bin/qemu-system-x86_64"
kernel = "/opt/kata/share/kata-containers/vmlinuz.container"
image = "/opt/kata/share/kata-containers/kata-containers.img"
machine_type = "pc"

# Optional space-separated list of options to pass to the guest kernel.
# For example, use `kernel_params = "vsyscall=emulate"` if you are having
# trouble running pre-2.15 glibc.
#
# WARNING: - any parameter specified here will take priority over the default
# parameter value of the same name used to start the virtual machine.
# Do not set values here unless you understand the impact of doing so as you
# may stop the virtual machine from booting.
# To see the list of default parameters, enable hypervisor debug, create a
# container and look for 'default-kernel-parameters' log entries.
kernel_params = ""

# Path to the firmware.
# If you want that qemu uses the default firmware leave this option empty
firmware = ""

# Machine accelerators
# comma-separated list of machine accelerators to pass to the hypervisor.
# For example, `machine_accelerators = "nosmm,nosmbus,nosata,nopit,static-prt,nofw"`
machine_accelerators=""

# Default number of vCPUs per SB/VM:
# unspecified or 0                --> will be set to 1
# < 0                             --> will be set to the actual number of physical cores
# > 0 <= number of physical cores --> will be set to the specified number
# > number of physical cores      --> will be set to the actual number of physical cores
default_vcpus = 1

# Default maximum number of vCPUs per SB/VM:
# unspecified or == 0             --> will be set to the actual number of physical cores or to the maximum number
#                                     of vCPUs supported by KVM if that number is exceeded
# > 0 <= number of physical cores --> will be set to the specified number
# > number of physical cores      --> will be set to the actual number of physical cores or to the maximum number
#                                     of vCPUs supported by KVM if that number is exceeded
# WARNING: Depending of the architecture, the maximum number of vCPUs supported by KVM is used when
# the actual number of physical cores is greater than it.
# WARNING: Be aware that this value impacts the virtual machine's memory footprint and CPU
# the hotplug functionality. For example, `default_maxvcpus = 240` specifies that until 240 vCPUs
# can be added to a SB/VM, but the memory footprint will be big. Another example, with
# `default_maxvcpus = 8` the memory footprint will be small, but 8 will be the maximum number of
# vCPUs supported by the SB/VM. In general, we recommend that you do not edit this variable,
# unless you know what are you doing.
default_maxvcpus = 0

# Bridges can be used to hot plug devices.
# Limitations:
# * Currently only pci bridges are supported
# * Until 30 devices per bridge can be hot plugged.
# * Until 5 PCI bridges can be cold plugged per VM.
#   This limitation could be a bug in qemu or in the kernel
# Default number of bridges per SB/VM:
# unspecified or 0   --> will be set to 1
# > 1 <= 5           --> will be set to the specified number
# > 5                --> will be set to 5
default_bridges = 1

# Default memory size in MiB for SB/VM.
# If unspecified then it will be set 2048 MiB.
default_memory = 2048
#
# Default memory slots per SB/VM.
# If unspecified then it will be set 10.
# This is will determine the times that memory will be hotadded to sandbox/VM.
#memory_slots = 10

# The size in MiB will be plused to max memory of hypervisor.
# It is the memory address space for the NVDIMM devie.
# If set block storage driver (block_device_driver) to "nvdimm",
# should set memory_offset to the size of block device.
# Default 0
#memory_offset = 0

# Disable block device from being used for a container's rootfs.
# In case of a storage driver like devicemapper where a container's 
# root file system is backed by a block device, the block device is passed
# directly to the hypervisor for performance reasons. 
# This flag prevents the block device from being passed to the hypervisor, 
# 9pfs is used instead to pass the rootfs.
disable_block_device_use = false

# Shared file system type:
#   - virtio-9p (default)
#   - virtio-fs
shared_fs = "virtio-9p"

# Path to vhost-user-fs daemon.
virtio_fs_daemon = "/opt/kata/bin/virtiofsd-x86_64"

# Default size of DAX cache in MiB
virtio_fs_cache_size = 1024

# Cache mode:
#
#  - none
#    Metadata, data, and pathname lookup are not cached in guest. They are
#    always fetched from host and any changes are immediately pushed to host.
#
#  - auto
#    Metadata and pathname lookup cache expires after a configured amount of
#    time (default is 1 second). Data is cached while the file is open (close
#    to open consistency).
#
#  - always
#    Metadata, data, and pathname lookup are cached in guest and never expire.
virtio_fs_cache = "always"

# Block storage driver to be used for the hypervisor in case the container
# rootfs is backed by a block device. This is virtio-scsi, virtio-blk
# or nvdimm.
block_device_driver = "virtio-scsi"

# Specifies cache-related options will be set to block devices or not.
# Default false
#block_device_cache_set = true

# Specifies cache-related options for block devices.
# Denotes whether use of O_DIRECT (bypass the host page cache) is enabled.
# Default false
#block_device_cache_direct = true

# Specifies cache-related options for block devices.
# Denotes whether flush requests for the device are ignored.
# Default false
#block_device_cache_noflush = true

# Enable iothreads (data-plane) to be used. This causes IO to be
# handled in a separate IO thread. This is currently only implemented
# for SCSI.
#
enable_iothreads = false

# Enable pre allocation of VM RAM, default false
# Enabling this will result in lower container density
# as all of the memory will be allocated and locked
# This is useful when you want to reserve all the memory
# upfront or in the cases where you want memory latencies
# to be very predictable
# Default false
#enable_mem_prealloc = true

# Enable huge pages for VM RAM, default false
# Enabling this will result in the VM memory
# being allocated using huge pages.
# This is useful when you want to use vhost-user network
# stacks within the container. This will automatically 
# result in memory pre allocation
#enable_hugepages = true

# Enable file based guest memory support. The default is an empty string which
# will disable this feature. In the case of virtio-fs, this is enabled
# automatically and '/dev/shm' is used as the backing folder.
# This option will be ignored if VM templating is enabled.
#file_mem_backend = ""

# Enable swap of vm memory. Default false.
# The behaviour is undefined if mem_prealloc is also set to true
#enable_swap = true

# This option changes the default hypervisor and kernel parameters
# to enable debug output where available. This extra output is added
# to the proxy logs, but only when proxy debug is also enabled.
# 
# Default false
#enable_debug = true

# Disable the customizations done in the runtime when it detects
# that it is running on top a VMM. This will result in the runtime
# behaving as it would when running on bare metal.
# 
#disable_nesting_checks = true

# This is the msize used for 9p shares. It is the number of bytes 
# used for 9p packet payload.
#msize_9p = 8192

# If true and vsocks are supported, use vsocks to communicate directly
# with the agent and no proxy is started, otherwise use unix
# sockets and start a proxy to communicate with the agent.
# Default false
#use_vsock = true

# VFIO devices are hotplugged on a bridge by default. 
# Enable hotplugging on root bus. This may be required for devices with
# a large PCI bar, as this is a current limitation with hotplugging on 
# a bridge. This value is valid for "pc" machine type.
# Default false
#hotplug_vfio_on_root_bus = true

# If host doesn't support vhost_net, set to true. Thus we won't create vhost fds for nics.
# Default false
#disable_vhost_net = true
#
# Default entropy source.
# The path to a host source of entropy (including a real hardware RNG)
# /dev/urandom and /dev/random are two main options.
# Be aware that /dev/random is a blocking source of entropy.  If the host
# runs out of entropy, the VMs boot time will increase leading to get startup
# timeouts.
# The source of entropy /dev/urandom is non-blocking and provides a
# generally acceptable source of entropy. It should work well for pretty much
# all practical purposes.
#entropy_source= "/dev/urandom"

# Path to OCI hook binaries in the *guest rootfs*.
# This does not affect host-side hooks which must instead be added to
# the OCI spec passed to the runtime.
#
# You can create a rootfs with hooks by customizing the osbuilder scripts:
# https://github.com/kata-containers/osbuilder
#
# Hooks must be stored in a subdirectory of guest_hook_path according to their
# hook type, i.e. "guest_hook_path/{prestart,postart,poststop}".
# The agent will scan these directories for executable files and add them, in
# lexicographical order, to the lifecycle of the guest container.
# Hooks are executed in the runtime namespace of the guest. See the official documentation:
# https://github.com/opencontainers/runtime-spec/blob/v1.0.1/config.md#posix-platform-hooks
# Warnings will be logged if any error is encountered will scanning for hooks,
# but it will not abort container execution.
#guest_hook_path = "/usr/share/oci/hooks"

[factory]
# VM templating support. Once enabled, new VMs are created from template
# using vm cloning. They will share the same initial kernel, initramfs and
# agent memory by mapping it readonly. It helps speeding up new container
# creation and saves a lot of memory if there are many kata containers running
# on the same host.
#
# When disabled, new VMs are created from scratch.
#
# Note: Requires "initrd=" to be set ("image=" is not supported).
#
# Default false
#enable_template = true

# Specifies the path of template.
#
# Default "/run/vc/vm/template"
#template_path = "/run/vc/vm/template"

# The number of caches of VMCache:
# unspecified or == 0   --> VMCache is disabled
# > 0                   --> will be set to the specified number
#
# VMCache is a function that creates VMs as caches before using it.
# It helps speed up new container creation.
# The function consists of a server and some clients communicating
# through Unix socket.  The protocol is gRPC in protocols/cache/cache.proto.
# The VMCache server will create some VMs and cache them by factory cache.
# It will convert the VM to gRPC format and transport it when gets
# requestion from clients.
# Factory grpccache is the VMCache client.  It will request gRPC format
# VM and convert it back to a VM.  If VMCache function is enabled,
# kata-runtime will request VM from factory grpccache when it creates
# a new sandbox.
#
# Default 0
#vm_cache_number = 0

# Specify the address of the Unix socket that is used by VMCache.
#
# Default /var/run/kata-containers/cache.sock
#vm_cache_endpoint = "/var/run/kata-containers/cache.sock"

[proxy.kata]
path = "/opt/kata/libexec/kata-containers/kata-proxy"

# If enabled, proxy messages will be sent to the system log
# (default: disabled)
#enable_debug = true

[shim.kata]
path = "/opt/kata/libexec/kata-containers/kata-shim"

# If enabled, shim messages will be sent to the system log
# (default: disabled)
#enable_debug = true

# If enabled, the shim will create opentracing.io traces and spans.
# (See https://www.jaegertracing.io/docs/getting-started).
#
# Note: By default, the shim runs in a separate network namespace. Therefore,
# to allow it to send trace details to the Jaeger agent running on the host,
# it is necessary to set 'disable_new_netns=true' so that it runs in the host
# network namespace.
#
# (default: disabled)
#enable_tracing = true

[agent.kata]
# If enabled, make the agent display debug-level messages.
# (default: disabled)
#enable_debug = true

# Enable agent tracing.
#
# If enabled, the default trace mode is "dynamic" and the
# default trace type is "isolated". The trace mode and type are set
# explicity with the `trace_type=` and `trace_mode=` options.
#
# Notes:
#
# - Tracing is ONLY enabled when `enable_tracing` is set: explicitly
#   setting `trace_mode=` and/or `trace_type=` without setting `enable_tracing`
#   will NOT activate agent tracing.
#
# - See https://github.com/kata-containers/agent/blob/master/TRACING.md for
#   full details.
#
# (default: disabled)
#enable_tracing = true
#
#trace_mode = "dynamic"
#trace_type = "isolated"

[netmon]
# If enabled, the network monitoring process gets started when the
# sandbox is created. This allows for the detection of some additional
# network being added to the existing network namespace, after the
# sandbox has been created.
# (default: disabled)
#enable_netmon = true

# Specify the path to the netmon binary.
path = "/opt/kata/libexec/kata-containers/kata-netmon"

# If enabled, netmon messages will be sent to the system log
# (default: disabled)
#enable_debug = true

[runtime]
# If enabled, the runtime will log additional debug messages to the
# system log
# (default: disabled)
#enable_debug = true
#
# Internetworking model
# Determines how the VM should be connected to the
# the container network interface
# Options:
#
#   - bridged
#     Uses a linux bridge to interconnect the container interface to
#     the VM. Works for most cases except macvlan and ipvlan.
#
#   - macvtap
#     Used when the Container network interface can be bridged using
#     macvtap.
#
#   - none
#     Used when customize network. Only creates a tap device. No veth pair.
#
#   - tcfilter
#     Uses tc filter rules to redirect traffic from the network interface
#     provided by plugin to a tap interface connected to the VM.
#
internetworking_model="tcfilter"

# disable guest seccomp
# Determines whether container seccomp profiles are passed to the virtual
# machine and applied by the kata agent. If set to true, seccomp is not applied
# within the guest
# (default: true)
disable_guest_seccomp=true

# If enabled, the runtime will create opentracing.io traces and spans.
# (See https://www.jaegertracing.io/docs/getting-started).
# (default: disabled)
#enable_tracing = true

# If enabled, the runtime will not create a network namespace for shim and hypervisor processes.
# This option may have some potential impacts to your host. It should only be used when you know what you're doing.
# `disable_new_netns` conflicts with `enable_netmon`
# `disable_new_netns` conflicts with `internetworking_model=bridged` and `internetworking_model=macvtap`. It works only
# with `internetworking_model=none`. The tap device will be in the host network namespace and can connect to a bridge
# (like OVS) directly.
# If you are using docker, `disable_new_netns` only works with `docker run --net=none`
# (default: false)
#disable_new_netns = true

# Enabled experimental feature list, format: ["a", "b"].
# Experimental features are features not stable enough for production,
# They may break compatibility, and are prepared for a big version bump.
# Supported experimental features:
# 1. "newstore": new persist storage driver which breaks backward compatibility,
#				expected to move out of experimental in 2.0.0.
# (default: [])
experimental=[]

Config file /usr/share/defaults/kata-containers/configuration.toml not found

---

KSM throttler

version

Output of " --version":

./kata-collect-data.sh: line 178: --version: command not found

systemd service

Image details

---
osbuilder:
  url: "https://github.com/kata-containers/osbuilder"
  version: "1.7.0-rc1-1afb7e56854f16892b22312b5cc07b55fa0ea221"
rootfs-creation-time: "2019-05-22T04:09:05.860112951+0000Z"
description: "osbuilder rootfs"
file-format-version: "0.0.2"
architecture: "x86_64"
base-distro:
  name: "bionic"
  version: "18.04"
  packages:
    default:
      - "systemd,iptables,init,chrony,fuse,bash"
    extra:
      - "bash"
      - "fuse"
agent:
  url: "https://github.com/kata-containers/agent"
  name: "kata-agent"
  version: "1.7.0-714bf625cc68505f31d802f98b84bf2b8006e146"
  agent-is-init-daemon: "no"

---

Initrd details

No initrd

---

Logfiles

Runtime logs

No recent runtime problems found in system journal.

Proxy logs

No recent proxy problems found in system journal.

Shim logs

No recent shim problems found in system journal.

Throttler logs

No recent throttler problems found in system journal.

---

Container manager details

Have docker

Docker

Output of "docker version":

Client:
 Version:           18.06.3-ce
 API version:       1.38
 Go version:        go1.10.8
 Git commit:        d7080c1
 Built:             Tue Feb 19 23:07:53 2019
 OS/Arch:           linux/amd64
 Experimental:      false
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Output of "docker info":

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Output of "systemctl show docker":

Restart=no
NotifyAccess=none
RestartUSec=100ms
TimeoutStartUSec=1min 30s
TimeoutStopUSec=1min 30s
RuntimeMaxUSec=infinity
WatchdogUSec=0
WatchdogTimestampMonotonic=0
RootDirectoryStartOnly=no
RemainAfterExit=no
GuessMainPID=yes
MainPID=0
ControlPID=0
FileDescriptorStoreMax=0
NFileDescriptorStore=0
StatusErrno=0
Result=success
UID=[not set]
GID=[not set]
NRestarts=0
ExecMainStartTimestampMonotonic=0
ExecMainExitTimestampMonotonic=0
ExecMainPID=0
ExecMainCode=0
ExecMainStatus=0
MemoryCurrent=[not set]
CPUUsageNSec=[not set]
TasksCurrent=[not set]
IPIngressBytes=18446744073709551615
IPIngressPackets=18446744073709551615
IPEgressBytes=18446744073709551615
IPEgressPackets=18446744073709551615
Delegate=no
CPUAccounting=no
CPUWeight=[not set]
StartupCPUWeight=[not set]
CPUShares=[not set]
StartupCPUShares=[not set]
CPUQuotaPerSecUSec=infinity
IOAccounting=no
IOWeight=[not set]
StartupIOWeight=[not set]
BlockIOAccounting=no
BlockIOWeight=[not set]
StartupBlockIOWeight=[not set]
MemoryAccounting=yes
MemoryMin=0
MemoryLow=0
MemoryHigh=infinity
MemoryMax=infinity
MemorySwapMax=infinity
MemoryLimit=infinity
DevicePolicy=auto
TasksAccounting=yes
TasksMax=73727
IPAccounting=no
UMask=0022
LimitCPU=infinity
LimitCPUSoft=infinity
LimitFSIZE=infinity
LimitFSIZESoft=infinity
LimitDATA=infinity
LimitDATASoft=infinity
LimitSTACK=infinity
LimitSTACKSoft=8388608
LimitCORE=infinity
LimitCORESoft=infinity
LimitRSS=infinity
LimitRSSSoft=infinity
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
LimitAS=infinity
LimitASSoft=infinity
LimitNPROC=2063281
LimitNPROCSoft=2063281
LimitMEMLOCK=67108864
LimitMEMLOCKSoft=67108864
LimitLOCKS=infinity
LimitLOCKSSoft=infinity
LimitSIGPENDING=2063281
LimitSIGPENDINGSoft=2063281
LimitMSGQUEUE=819200
LimitMSGQUEUESoft=819200
LimitNICE=0
LimitNICESoft=0
LimitRTPRIO=0
LimitRTPRIOSoft=0
LimitRTTIME=infinity
LimitRTTIMESoft=infinity
OOMScoreAdjust=0
Nice=0
IOSchedulingClass=0
IOSchedulingPriority=0
CPUSchedulingPolicy=0
CPUSchedulingPriority=0
TimerSlackNSec=50000
CPUSchedulingResetOnFork=no
NonBlocking=no
StandardInput=null
StandardInputData=
StandardOutput=inherit
StandardError=inherit
TTYReset=no
TTYVHangup=no
TTYVTDisallocate=no
SyslogPriority=30
SyslogLevelPrefix=yes
SyslogLevel=6
SyslogFacility=3
LogLevelMax=-1
LogRateLimitIntervalUSec=0
LogRateLimitBurst=0
SecureBits=0
CapabilityBoundingSet=cap_chown cap_dac_override cap_dac_read_search cap_fowner cap_fsetid cap_kill cap_setgid cap_setuid cap_setpcap cap_linux_immutable cap_net_bind_service cap_net_broadcast cap_net_admin cap_net_raw cap_ipc_lock cap_ipc_owner cap_sys_module cap_sys_rawio cap_sys_chroot cap_sys_ptrace cap_sys_pacct cap_sys_admin cap_sys_boot cap_sys_nice cap_sys_resource cap_sys_time cap_sys_tty_config cap_mknod cap_lease cap_audit_write cap_audit_control cap_setfcap cap_mac_override cap_mac_admin cap_syslog cap_wake_alarm cap_block_suspend
AmbientCapabilities=
DynamicUser=no
RemoveIPC=no
MountFlags=
PrivateTmp=no
PrivateDevices=no
ProtectKernelTunables=no
ProtectKernelModules=no
ProtectControlGroups=no
PrivateNetwork=no
PrivateUsers=no
PrivateMounts=no
ProtectHome=no
ProtectSystem=no
SameProcessGroup=no
UtmpMode=init
IgnoreSIGPIPE=yes
NoNewPrivileges=no
SystemCallErrorNumber=0
LockPersonality=no
RuntimeDirectoryPreserve=no
RuntimeDirectoryMode=0755
StateDirectoryMode=0755
CacheDirectoryMode=0755
LogsDirectoryMode=0755
ConfigurationDirectoryMode=0755
MemoryDenyWriteExecute=no
RestrictRealtime=no
RestrictNamespaces=no
MountAPIVFS=no
KeyringMode=private
KillMode=control-group
KillSignal=15
FinalKillSignal=9
SendSIGKILL=yes
SendSIGHUP=no
WatchdogSignal=6
Id=docker.service
Names=docker.service
WantedBy=kitt-init.service
ConsistsOf=docker.socket
Before=kitt-init.service
After=docker.socket
TriggeredBy=docker.socket
Description=docker.service
LoadState=masked
ActiveState=inactive
SubState=dead
FragmentPath=/dev/null
UnitFileState=masked
StateChangeTimestampMonotonic=0
InactiveExitTimestampMonotonic=0
ActiveEnterTimestampMonotonic=0
ActiveExitTimestampMonotonic=0
InactiveEnterTimestampMonotonic=0
CanStart=no
CanStop=yes
CanReload=no
CanIsolate=no
StopWhenUnneeded=no
RefuseManualStart=no
RefuseManualStop=no
AllowIsolate=no
DefaultDependencies=yes
OnFailureJobMode=replace
IgnoreOnIsolate=no
NeedDaemonReload=no
JobTimeoutUSec=infinity
JobRunningTimeoutUSec=infinity
JobTimeoutAction=none
ConditionResult=no
AssertResult=no
ConditionTimestampMonotonic=0
AssertTimestampMonotonic=0
LoadError=org.freedesktop.systemd1.UnitMasked "Unit docker.service is masked."
Transient=no
Perpetual=no
StartLimitIntervalUSec=10s
StartLimitBurst=5
StartLimitAction=none
FailureAction=none
FailureActionExitStatus=-1
SuccessAction=none
SuccessActionExitStatus=-1
CollectMode=inactive

No kubectl
No crio
Have containerd

containerd

Output of "containerd --version":

containerd github.com/containerd/containerd v1.2.6 894b81a4b802e4eb2a91d1ce216b8817763c29fb

Output of "systemctl show containerd":

Type=simple
Restart=always
NotifyAccess=none
RestartUSec=5s
TimeoutStartUSec=1min 30s
TimeoutStopUSec=1min 30s
RuntimeMaxUSec=infinity
WatchdogUSec=0
WatchdogTimestampMonotonic=0
RootDirectoryStartOnly=no
RemainAfterExit=no
GuessMainPID=yes
MainPID=2924
ControlPID=0
FileDescriptorStoreMax=0
NFileDescriptorStore=0
StatusErrno=0
Result=success
UID=[not set]
GID=[not set]
NRestarts=0
ExecMainStartTimestamp=Fri 2019-06-21 06:46:20 UTC
ExecMainStartTimestampMonotonic=66297538
ExecMainExitTimestampMonotonic=0
ExecMainPID=2924
ExecMainCode=0
ExecMainStatus=0
ExecStartPre={ path=/sbin/modprobe ; argv[]=/sbin/modprobe overlay ; ignore_errors=no ; start_time=[Fri 2019-06-21 06:46:18 UTC] ; stop_time=[Fri 2019-06-21 06:46:18 UTC] ; pid=2850 ; code=exited ; status=0 }
ExecStartPre={ path=/opt/bin/containerd-init.sh ; argv[]=/opt/bin/containerd-init.sh ; ignore_errors=no ; start_time=[Fri 2019-06-21 06:46:18 UTC] ; stop_time=[Fri 2019-06-21 06:46:20 UTC] ; pid=2852 ; code=exited ; status=0 }
ExecStart={ path=/opt/containerd/bin/containerd ; argv[]=/opt/containerd/bin/containerd --log-level=debug --config=/etc/containerd/config.toml ; ignore_errors=no ; start_time=[Fri 2019-06-21 06:46:20 UTC] ; stop_time=[n/a] ; pid=2924 ; code=(null) ; status=0/0 }
Slice=system.slice
ControlGroup=/system.slice/containerd.service
MemoryCurrent=2239016960
CPUUsageNSec=[not set]
TasksCurrent=290
IPIngressBytes=18446744073709551615
IPIngressPackets=18446744073709551615
IPEgressBytes=18446744073709551615
IPEgressPackets=18446744073709551615
Delegate=yes
DelegateControllers=cpu cpuacct io blkio memory devices pids bpf-firewall bpf-devices
CPUAccounting=no
CPUWeight=[not set]
StartupCPUWeight=[not set]
CPUShares=[not set]
StartupCPUShares=[not set]
CPUQuotaPerSecUSec=infinity
IOAccounting=no
IOWeight=[not set]
StartupIOWeight=[not set]
BlockIOAccounting=no
BlockIOWeight=[not set]
StartupBlockIOWeight=[not set]
MemoryAccounting=yes
MemoryMin=0
MemoryLow=0
MemoryHigh=infinity
MemoryMax=infinity
MemorySwapMax=infinity
MemoryLimit=infinity
DevicePolicy=auto
TasksAccounting=yes
TasksMax=73727
IPAccounting=no
UMask=0022
LimitCPU=infinity
LimitCPUSoft=infinity
LimitFSIZE=infinity
LimitFSIZESoft=infinity
LimitDATA=infinity
LimitDATASoft=infinity
LimitSTACK=infinity
LimitSTACKSoft=8388608
LimitCORE=infinity
LimitCORESoft=infinity
LimitRSS=infinity
LimitRSSSoft=infinity
LimitNOFILE=1048576
LimitNOFILESoft=1048576
LimitAS=infinity
LimitASSoft=infinity
LimitNPROC=infinity
LimitNPROCSoft=infinity
LimitMEMLOCK=65536
LimitMEMLOCKSoft=65536
LimitLOCKS=infinity
LimitLOCKSSoft=infinity
LimitSIGPENDING=2063281
LimitSIGPENDINGSoft=2063281
LimitMSGQUEUE=819200
LimitMSGQUEUESoft=819200
LimitNICE=0
LimitNICESoft=0
LimitRTPRIO=0
LimitRTPRIOSoft=0
LimitRTTIME=infinity
LimitRTTIMESoft=infinity
OOMScoreAdjust=-999
Nice=0
IOSchedulingClass=0
IOSchedulingPriority=0
CPUSchedulingPolicy=0
CPUSchedulingPriority=0
TimerSlackNSec=50000
CPUSchedulingResetOnFork=no
NonBlocking=no
StandardInput=null
StandardInputData=
StandardOutput=journal
StandardError=inherit
TTYReset=no
TTYVHangup=no
TTYVTDisallocate=no
SyslogPriority=30
SyslogLevelPrefix=yes
SyslogLevel=6
SyslogFacility=3
LogLevelMax=-1
LogRateLimitIntervalUSec=0
LogRateLimitBurst=0
SecureBits=0
CapabilityBoundingSet=cap_chown cap_dac_override cap_dac_read_search cap_fowner cap_fsetid cap_kill cap_setgid cap_setuid cap_setpcap cap_linux_immutable cap_net_bind_service cap_net_broadcast cap_net_admin cap_net_raw cap_ipc_lock cap_ipc_owner cap_sys_module cap_sys_rawio cap_sys_chroot cap_sys_ptrace cap_sys_pacct cap_sys_admin cap_sys_boot cap_sys_nice cap_sys_resource cap_sys_time cap_sys_tty_config cap_mknod cap_lease cap_audit_write cap_audit_control cap_setfcap cap_mac_override cap_mac_admin cap_syslog cap_wake_alarm cap_block_suspend
AmbientCapabilities=
DynamicUser=no
RemoveIPC=no
MountFlags=
PrivateTmp=no
PrivateDevices=no
ProtectKernelTunables=no
ProtectKernelModules=no
ProtectControlGroups=no
PrivateNetwork=no
PrivateUsers=no
PrivateMounts=no
ProtectHome=no
ProtectSystem=no
SameProcessGroup=no
UtmpMode=init
IgnoreSIGPIPE=yes
NoNewPrivileges=no
SystemCallErrorNumber=0
LockPersonality=no
RuntimeDirectoryPreserve=no
RuntimeDirectoryMode=0755
StateDirectoryMode=0755
CacheDirectoryMode=0755
LogsDirectoryMode=0755
ConfigurationDirectoryMode=0755
MemoryDenyWriteExecute=no
RestrictRealtime=no
RestrictNamespaces=no
MountAPIVFS=no
KeyringMode=private
KillMode=process
KillSignal=15
FinalKillSignal=9
SendSIGKILL=yes
SendSIGHUP=no
WatchdogSignal=6
Id=containerd.service
Names=containerd.service
Requires=sysinit.target system.slice
WantedBy=multi-user.target
Conflicts=shutdown.target
Before=multi-user.target shutdown.target
After=basic.target systemd-journald.socket kata-init.service system.slice sysinit.target containerd-devicemapper-init.service
Documentation=https://containerd.io
Description=containerd container runtime
LoadState=loaded
ActiveState=active
SubState=running
FragmentPath=/etc/systemd/system/containerd.service
UnitFileState=enabled
UnitFilePreset=enabled
StateChangeTimestamp=Fri 2019-06-21 06:46:20 UTC
StateChangeTimestampMonotonic=66297589
InactiveExitTimestamp=Fri 2019-06-21 06:46:18 UTC
InactiveExitTimestampMonotonic=64328825
ActiveEnterTimestamp=Fri 2019-06-21 06:46:20 UTC
ActiveEnterTimestampMonotonic=66297589
ActiveExitTimestampMonotonic=0
InactiveEnterTimestampMonotonic=0
CanStart=yes
CanStop=yes
CanReload=no
CanIsolate=no
StopWhenUnneeded=no
RefuseManualStart=no
RefuseManualStop=no
AllowIsolate=no
DefaultDependencies=yes
OnFailureJobMode=replace
IgnoreOnIsolate=no
NeedDaemonReload=no
JobTimeoutUSec=infinity
JobRunningTimeoutUSec=infinity
JobTimeoutAction=none
ConditionResult=yes
AssertResult=yes
ConditionTimestamp=Fri 2019-06-21 06:46:18 UTC
ConditionTimestampMonotonic=64327507
AssertTimestamp=Fri 2019-06-21 06:46:18 UTC
AssertTimestampMonotonic=64327507
Transient=no
Perpetual=no
StartLimitIntervalUSec=10s
StartLimitBurst=5
StartLimitAction=none
FailureAction=none
FailureActionExitStatus=-1
SuccessAction=none
SuccessActionExitStatus=-1
InvocationID=46f1cc9369fd4feea631193cd86c8470
CollectMode=inactive

Output of "cat /etc/containerd/config.toml":

[grpc]
address = "/run/containerd/containerd.sock"
uid = 0
gid = 0

[plugins]
  [plugins.cri.containerd]
    snapshotter = "overlayfs"
    [plugins.cri.containerd.default_runtime]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/bin/runc"
      runtime_root = ""
    [plugins.cri.containerd.untrusted_workload_runtime]
      runtime_type = "io.containerd.kata.v2"

[plugins.cri]
  max_container_log_line_size = 262144

[plugins.linux]
  shim = "/opt/containerd/bin/containerd-shim"
  runtime = "runc"

[plugins.cri.registry]
  [plugins.cri.registry.mirrors]
    [plugins.cri.registry.mirrors."docker.io"]
       endpoint = []

---

Packages

No dpkg
No rpm

---

[egernst]

/cc @amshinde @mcastelino @sboeuf

[sboeuf]

Just spent some time with @amshinde on this issue. The problem is the same for both 9p and virtio-fs. Because you create the host-emptydir inside / and because / is the actual shared directory, whenever you create a 100G file inside the host-emptydir (from a container perspective), you see this file being created on the host under /run/katacontainers/<pod_id>/.... That's why tmpfs is growing.

The simple solution is to not ignore the host-emptydir created by k8s and simply bind mount it inside the shared directory on the host. This way, everytime you want to create 100G file from the container, it will be created all the way back into the directory provided by k8s.

The only question raised was about performance because now we will have to go over the guest/host boundary when using this empty dir. Well the answer is that if you expect performance out of this directory, you should use it as Memory, this way it will directly rely on the tmpfs inside the guest.
And if you think about virtio-fs, because it will be as performant as block, you might not see any difference with how it performs right now in the context of block.
The only case where we would see a difference would be the combo block(for container rootfs) and 9p for the empty dir, but who really cares about 9p?

[awprice]

Bind mounting the shared directory created by k8s on the host sounds like a solid plan. Where would a good place to start to solve this?

Ideally if someone wanted performance with an emptyDir, they should be using medium: Memory.

[amshinde]

@awprice What @sboeuf was referring to was essentially reverting #1485 or special casing it for devicemapper.

We bind-mount all the container rootfs under /run/katacontainers/<pod_id>/... which kind of explains the increase in disk usage for /run.

[amshinde]

@awprice I thought with #1485, we are creating the emptydirs in the sandbox rootfs.
But I am surprised to see the directory created outside the sandbox rootfs as:

ls 58e6c1ac260f08dae65bea58ffff0b175caf8e41087951befd6b6191ac594af9/58e6c1ac260f08dae65bea58ffff0b175caf8e41087951befd6b6191ac594af9/
local  rootfs

I think the local directory needs to created under the sandbox rootfs directory, which could explain the memory usage under /run. Will try to dig deeper and post my findings here.

[awprice]

Nice find @amshinde! This is where the path is constructed -

runtime/virtcontainers/kata_agent.go

Line 1297 in 3d4729d

mounts[idx].Source = filepath.Join(kataGuestSharedDir, sandboxID, KataLocalDevType, filepath.Base(mnt.Source))

As you said, maybe we need to move local into the rootfs directory?

[sboeuf]

@awprice @amshinde

maybe we need to move local into the rootfs directory

That's an option, but you have to keep in mind that by doing so, you're using the space made available by the container rootfs overlay snapshot. And this space might not be as large as you could expect the host-emptydir directory provided by k8s on the host. That's why I would suggest to treat this empty directory as any other directory that we share between host and guest.
Unless I'm missing some context, it really seems that only the Memory emptyDir directories should have special treatment.

[awprice]

@sboeuf The original intention behind #1485 was to provision emptyDir inside the sandbox container, and so if the user was using devicemapper, emptyDir would benefit from the speed of devicemapper.

That's why I would suggest to treat this empty directory as any other directory that we share between host and guest.

I've tested this behaviour with virtio-fs, and reverting the changes made in #1485 would achieve this. I haven't tested 9p, but I think it would work the same as virtio-fs.

Where you lose out is if you use devicemapper, the emptyDir will be shared with virtio-fs/9p and you won't benefit from the performance of devicemapper.

[sboeuf]

@awprice

Where you lose out is if you use devicemapper, the emptyDir will be shared with virtio-fs/9p and you won't benefit from the performance of devicemapper.

True, but as we discussed, one should use Memory emptyDir if he wants to get performance out of empty directories. And in this case, devicemapper or not, things are the same.

And secondly, I expect virtio-fs to be as performant as block if used with correct parameters, which means you should have equivalent performances.

[amshinde]

@sboeuf @awprice I would like to keep #1485 around, till we move virtio-fs to a stable feature.
Once we deprecate 9p for good, we can then get rid of #1485.

@awprice I think this patch should fix the issue you are seeing:

diff --git a/virtcontainers/kata_agent.go b/virtcontainers/kata_agent.go
index c9451f0..61e739d 100644
--- a/virtcontainers/kata_agent.go
+++ b/virtcontainers/kata_agent.go
@@ -1173,7 +1173,7 @@ func (k *kataAgent) createContainer(sandbox *Sandbox, c *Container) (p *Process,
        epheStorages := k.handleEphemeralStorage(ociSpec.Mounts)
        ctrStorages = append(ctrStorages, epheStorages...)
 
-       localStorages := k.handleLocalStorage(ociSpec.Mounts, sandbox.id)
+       localStorages := k.handleLocalStorage(ociSpec.Mounts, sandbox.id, c.rootfsSuffix)
        ctrStorages = append(ctrStorages, localStorages...)
 
        // We replace all OCI mount sources that match our container mount
@@ -1285,7 +1285,7 @@ func (k *kataAgent) handleEphemeralStorage(mounts []specs.Mount) []*grpc.Storage
 
 // handleLocalStorage handles local storage within the VM
 // by creating a directory in the VM from the source of the mount point.
-func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string) []*grpc.Storage {
+func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string, rootfsSuffix string) []*grpc.Storage {
        var localStorages []*grpc.Storage
        for idx, mnt := range mounts {
                if mnt.Type == KataLocalDevType {
@@ -1294,7 +1294,7 @@ func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string) [
                        // We rely on the fact that the first container in the VM has the same ID as the sandbox ID.
                        // In Kubernetes, this is usually the pause container and we depend on it existing for
                        // local directories to work.
-                       mounts[idx].Source = filepath.Join(kataGuestSharedDir, sandboxID, KataLocalDevType, filepath.Base(mnt.Source))
+                       mounts[idx].Source = filepath.Join(kataGuestSharedDir, sandboxID, rootfsSuffix, KataLocalDevType, filepath.Base(mnt.Source))
 
                        // Create a storage struct so that the kata agent is able to create the
                        // directory inside the VM.

Let me know if that works for you.

[awprice]

Thanks @amshinde, I will give that a test as soon as possible.

[awprice]

@amshinde I've tested your PR and can confirm it fixes this issue. When running the dd command to create the 100gb file, it is now being created on disk, rather than in memory.