Start a look at resource checking examples

34_checking_resources/CGROUPS.md

@@ -0,0 +1,53 @@
+# README
+Demonstrate how to work with cgroups
+
+## cgroups 
+```sh
+# man pages
+man cgroups
+
+# list filesystems and look at cgroups
+cat /proc/filesystems  
+
+# see where they a virtually mounted
+mount
+```
+
+## Install tooling
+```sh
+# install tooling
+sudo apt install cgroup-tools        
+
+# list cgroup tools
+dpkg -L cgroup-tools | grep bin        
+
+```
+
+## Walk the filesystem
+```sh
+# cgroups v1
+ls /sys/fs/cgroup/
+
+# cgroups v2
+ls /sys/fs/cgroup/unified     
+```
+
+
+## Resources
+https://medium.com/nttlabs/cgroup-v2-596d035be4d7
+
+
+https://opensource.com/article/20/10/cgroups
+
+https://www.linuxjournal.com/content/everything-you-need-know-about-linux-containers-part-i-linux-control-groups-and-process
+
+https://www.linuxjournal.com/content/everything-you-need-know-about-linux-containers-part-ii-working-linux-containers-lxc
+
+
+SSH in a cgroup
+https://unix.stackexchange.com/questions/209199/how-to-ensure-ssh-via-cgroups-on-centos
+
+https://unix.stackexchange.com/questions/56538/controlling-priority-of-applications-using-cgroups
+
+cgroupsv2
+https://unix.stackexchange.com/questions/471476/how-do-i-check-cgroup-v2-is-installed-on-my-machine

34_checking_resources/README.md

@@ -0,0 +1,101 @@
+# Checking Resources
+
+Demonstrate how to use various commands to verify resource usage in the OS.
+
+REF: [14_interrogate_resources](https://github.com/chrisguest75/sysadmin_examples/tree/master/14_interrogate_resources)  
+
+TODO:
+
+* cgroups
+* Open sockets
+* Free memory
+* File handles
+* Look at the brenden gregg resources http://www.brendangregg.com/linuxperf.html
+* Filesystem
+* Procfs
+* debugfs
+* https://github.com/raboof/nethogs
+
+
+```sh
+# booted with
+cat /proc/cmdline 
+
+# built with
+cat /boot/config-5.8.0-49-generic | grep CGROUP
+
+# global limits
+systemctl show     
+```
+
+## Check limits
+
+```sh
+# limits inside a container
+docker run -it ubuntu:20.04 /bin/bash -c "ulimit -a" 
+
+# limits on host
+ulimit -a 
+
+# limits for current pid
+cat /proc/$$/limits 
+
+# show global config
+systemctl show    
+```
+
+## Disk
+
+```sh
+# free space
+df -h
+```
+
+## Sockets
+
+```sh
+# summary of all the sockets
+ss -s 
+
+# listening sockets
+ss -l 
+
+# listening sockets with processes
+sudo ss -lp
+
+# tcp connections with information
+ss -ti 
+```
+
+
+## Memory
+
+```sh
+free -h
+
+vmstat 
+```
+
+## IO
+
+[sysstat](https://www.linux.com/training-tutorials/sysstat-howto-deployment-and-configuration-guide-linux-servers/)  
+
+```sh
+
+sudo apt install sysstat   
+
+# cpu usage
+mpstat -A
+
+
+
+```
+
+
+
+top
+systemd-cgtop   
+systemd-analyze blame 
+
+systemctl list-units -t service        
+

README.md

@@ -215,6 +215,11 @@ Steps [README.md](./32_jq/README.md)
 Demonstrates using awscli to query resources in an AWS account.  
 Steps [README.md](./33_awscli/README.md)  
 
+## Example 34 - Checking Resources
+
+Demonstrate how to use various commands to verify resource usage in the OS.  
+Steps [README.md](./34_checking_resources/README.md)  
+
 ## Example 35 - APT and DPKG
 
 Demonstrate examples of working with APT and DPKG  
@@ -285,9 +290,9 @@ Steps [README.md](./53_sync_files/README.md)
 Demonstrate date handling in shell.  
 Steps [README.md](./54_date_handling/README.md)  
 
-## TODO
-
+## TODO:
   * oh-my-zsh and oh-my-bash
+  * Globbing 
   * Process Substition versus command substitution < <() < $()
   * Detecting dotsourcing.
         https://stackoverflow.com/questions/2683279/how-to-detect-if-a-script-is-being-sourced