Docker Lab Day 2
What is docker update ?
We can change the configurations of an already running container which is observed by the docker server for > 10 seconds in the following test which we are going to run using the restart policy.
docker update --restart always test-update
Then went inside the container using bash and killed it using process id 1
docker exec -it test-update /bin/bash root@a7eb846de486:/usr/local/apache2# kill 1
Although the container got terminated by itself still due to restart policy came back again
root@a7eb846de486:/usr/local/apache2# [root@ip-172-31-17-58 centos]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES a7eb846de486 httpd "httpd-foreground" 13 minutes ago Up 3 seconds 80/tcp test-update
One more thing to note is when we did a docker stop – then it did not restart. Why? Since this restart policy does not apply to manual stops to avoid restart cycle clashes.
What is docker wait ?
It waits even though we run in detached mode till 1/more container is stopped with exit code 0 – i.e. graceful exit
Till the time we had not put a command like –
docker stop 06ead66c7817d59c371a436350fe0f574823214609c608eda3632258fae6da4e
Post which we saw it exited as in line no. 2
[root@ip-172-31-17-58 centos]# docker run -itd ubuntu 06ead66c7817d59c371a436350fe0f574823214609c608eda3632258fae6da4e [root@ip-172-31-17-58 centos]# docker wait 06ead66c7817d59c371a436350fe0f574823214609c608eda3632258fae6da4e 0