View source for Docker/Current/Troubleshooting/Troubleshooting

{{ArticleUnstructured
|DisplayName=Troubleshooting
|Platform=PureEngage, PureConnect, PureCloud
|Context=Information about how to troubleshoot docker containers.
|Standalone=No
}}
==Troubleshooting Docker Containers==
<ol>
<li>Get the IP address. To do this, run the following command.
<source lang="xml"> docker inspect $(dl) | grep -wm1 IPAddress | cut -d '"' -f 4</source>Or, install jQuery and run the following command.
<source lang="xml">docker inspect $(dl) | jq -r '.[0].NetworkSettings.IPAddress'</source>Or install [https://docs.docker.com/engine/reference/commandline/inspect go template] and run the following command. <source lang="xml">docker inspect -f '{{ .NetworkSettings.IPAddress }}' <container_name></source> To pass a build argument when building an image from Dockerfile:
<source lang="xml">DOCKER_HOST_IP=`ifconfig | grep -E "([0-9]{1,3}\.){3}[0-9]{1,3}" | grep -v 127.0.0.1 | awk '{ print $2 }' | cut -f2 -d: | head -n1`
echo DOCKER_HOST_IP = $DOCKER_HOST_IP
docker build \
  --build-arg ARTIFACTORY_ADDRESS=$DOCKER_HOST_IP 
  -t sometag \
  some-directory/
</source></li>
<li>Get port mapping
<source lang="xml">docker inspect -f '{{range $p, $conf := .NetworkSettings.Ports}} {{$p}} -> {{(index $conf 0).HostPort}} {{end}}' <containername></source></li>
<li>Find containers by regular expression
<source lang="xml">for i in $(docker ps -a | grep "REGEXP_PATTERN" | cut -f1 -d" "); do echo $i; done</source></li>
<li>Get environment settings. 
<source lang="xml">docker run --rm ubuntu env</source></li>
<li>Kill running containers.
<source lang="xml">docker kill $(docker ps -q)</source></li>
<li>Delete all containers (force!! running or stopped containers).
<source lang="xml">docker rm -f $(docker ps -qa)</source></li>
<li>Delete old containers.
<source lang="xml">docker ps -a | grep 'weeks ago' | awk '{print $1}' | xargs docker rm</source></li>
<li>Delete stopped containers.
<source lang="xml">docker rm -v $(docker ps -a -q -f status=exited)</source></li>
<li>Delete containers after stopping.
<source lang="xml">docker stop $(docker ps -aq) && docker rm -v $(docker ps -aq)</source></li>
<li>Delete dangling images.
<source lang="xml">docker rmi $(docker images -q -f dangling=true)</source></li>
<li>Delete all images.
<source lang="xml">docker rmi $(docker images -q)</source></li>
<li>Delete dangling volumes.
As of Docker 1.9.0:
<source lang="xml">docker volume rm $(docker volume ls -q -f dangling=true)</source>
In 1.9.0, the filter dangling=false does not work. It is ignored and lists all volumes.</li>
<li> Show image dependencies.
<source lang="xml">docker images -viz | dot -Tpng -o docker.png</source></li>
<li>Slimming down Docker containers.
'''Cleaning APT in a RUN layer''':
This must be done in the same layer as that of the other APT commands. If not, the previous layers will still contain the original information and your images will still be large.
<source lang="xml">RUN {apt commands} \</source>
<source lang="xml"> && apt-get clean \</source>
<source lang="xml"> && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*</source>
'''Flatten an image''':
<source lang="xml">ID=$(docker run -d image-name /bin/bash)</source>
<source lang="xml">docker export $ID | docker import – flat-image-name</source>
'''For backup''':
<source lang="xml">ID=$(docker run -d image-name /bin/bash)</source>
<source lang="xml">(docker export $ID | gzip -c > image.tgz)</source>
<source lang="xml">gzip -dc image.tgz | docker import - flat-image-name</source></li>
</ol>

== Information on Running Docker Containers ==
* <code>docker ps</code> displays running containers.
* <code>docker logs</code> gets logs from the container. (You can use a custom log driver, but logs are available only for json-file and journald in 1.10).
* <code>docker inspect</code> inspects all the information of a container (including the IP address).
* <code>docker events</code> gets events from the container.
* <code>docker port</code> displays the public facing port of the container.
* <code>docker top</code> displays the running processes in container.
* <code>docker stats</code> displays the containers' resource usage statistics.
* <code>docker diff</code> displays the changed files in the container's FS.
* <code>docker ps -a</code> displays running and stopped containers.
* <code>docker stats --all</code> displays a running list of containers.
* <code>docker update</code> updates a container's resource limits.

To check the CPU, memory, and network I/O usage of a single container:
<source lang="xml">docker stats <container></source>
For all containers listed by ID:
<source lang="xml">docker stats $(docker ps -q)</source>
For all containers listed by name:
<source lang="xml">docker stats $(docker ps --format '{{.Names}}')</source>
For all containers listed by image:
<source lang="xml">docker ps -a -f ancestor=ubuntu</source>
To remove all untagged images:
<source lang="xml">docker rmi $(docker images | grep “^” | awk '{split($0,a," "); print a[3]}')</source>
To remove container by a regular expression:
<source lang="xml">docker ps -a | grep wildfly | awk '{print $1}' | xargs docker rm -f</source>
To remove all exited containers:
<source lang="xml">docker rm -f $(docker ps -a | grep Exit | awk '{ print $1 }')</source>