Explain docker update & docker wait commands with example

Docker update

Update command is used to update the CPU and memory configuration of the container. Available options can be checked with docker update –help command

[root@ip-172-31-7-71 centos]# docker update --help

Usage:  docker update [OPTIONS] CONTAINER [CONTAINER...]

Update configuration of one or more containers

Options:
      --blkio-weight uint16        Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)
      --cpu-period int             Limit CPU CFS (Completely Fair Scheduler) period
      --cpu-quota int              Limit CPU CFS (Completely Fair Scheduler) quota
      --cpu-rt-period int          Limit the CPU real-time period in microseconds
      --cpu-rt-runtime int         Limit the CPU real-time runtime in microseconds
  -c, --cpu-shares int             CPU shares (relative weight)
      --cpus decimal               Number of CPUs
      --cpuset-cpus string         CPUs in which to allow execution (0-3, 0,1)
      --cpuset-mems string         MEMs in which to allow execution (0-3, 0,1)
      --kernel-memory bytes        Kernel memory limit
  -m, --memory bytes               Memory limit
      --memory-reservation bytes   Memory soft limit
      --memory-swap bytes          Swap limit equal to memory plus swap: '-1' to enable unlimited swap
      --pids-limit int             Tune container pids limit (set -1 for unlimited)
      --restart string             Restart policy to apply when a container exits
[root@ip-172-31-7-71 centos]#

Example : docker update 436662ff3488 --restart always

docker wait

docker wait command waits for one or more container to exit and provides the return status of the docker exit

[root@ip-172-31-7-71 centos]# docker wait 95d0f2b4f8cf
143
[root@ip-172-31-7-71 centos]#

In the above example docker wait command gives the output when container 95d0f2b4f8cf was stopped