add start to cgroups

28_checking_resources/README.md

@@ -12,6 +12,10 @@ TODO:
 * debugfs
 https://github.com/raboof/nethogs
 
+## Check limits
+```sh
+ulimit -a
+```
 ## Disk
 
 ```sh
@@ -22,9 +26,20 @@ 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

34_checking_resources/CGROUPS.md

@@ -0,0 +1,30 @@
+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
+
+## Limits
+docker run -it ubuntu:20.04 /bin/bash -c "ulimit -a" 
+
+ulimit -a 
+
+cat /proc/$$/limits 
+
+## Cgroups 
+```sh
+cat /proc/filesystems  
+mount
+```
+
+```sh
+ls /sys/fs/cgroup/
+```
+