create links for ephemeral storage devices #1173
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tjkirch
approved these changes
Oct 19, 2020
Some EC2 instance types come with disks that are physically connected to the host. Kubernetes can use these as local persistent volumes in conjunction with an external static provisioner. To make it easier to configure the static provisioner, we now create symlinks to known ephemeral disk devices in /dev/disk/ephemeral. Incorrectly identifying a device as an ephemeral when it is not could cause irrecoverable data loss. Hence we take an "allowlist" approach where only specific device types are included, and check for known partition types as an additional safeguard.
Warn about giving containers access to block devices, since this can lead to host compromise even if the system disks are not exposed. Signed-off-by: Ben Cressey <bcressey@amazon.com>
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tjkirch
approved these changes
Oct 21, 2020
samuelkarp
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Oct 23, 2020
samuelkarp
approved these changes
Oct 23, 2020
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Issue number:
#1088
Description of changes:
Populate
/dev/disk/ephemeralwith links to ephemeral storage devices.Update security guidance to reflect the risks of mapping a block device into an untrusted container.
Testing done:
Verified that the two ephemeral disks were linked on an
m5ad.4xlarge:Verified that other disks were classified as "system":
Verified that the external static provisioner could discover the ephemeral disks:
Terms of contribution:
By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.