Docker Command Tricks & Tips

 

Docker container command Tips & Tricks

Here my idea is to use the Unix/Linux 'alias' command for most those common docker container, network, volume commands to form as short-cuts. This trick work on bash shell.

First examine the docker container listing with the --format options as follows.

docker container ps -s \
  --format "table {{.Names}}\t{{.Image}}\t{{.Status}}\t{{.Size}}"

docker ps command

To get the logs of any applications that runs in container

alias dkrlogs='docker logs'
alias dkrlogsf='docker logs -f '

docker logs with alias trick

List of the images

alias dkri='docker image ls'

docker image list alias trick

The container list

alias dkrcs='docker container ls'

docker container list alias trick

Remove the 'Exited' status container

alias dkrrm='docker rm'

docker rm alias trick

Docker top list to see the container inside process ID

alias dkrtop='docker top'

docker top alias trick

All the above nice commands will be helpful for the pipelines, Containerization makes CI/CD seamless. 

We could add the following alias lines to our .bashrc or .bashprofile where docker command executable:

alias dkrlogs='docker logs'
alias dkrlogsf='docker logs -f '
alias dkri='docker image ls'
alias dkrcs='docker container ls'
alias dkrrm='docker rm'
alias dkrtop='docker top'
alias cleanall='docker container rm $(docker ps -a -q)'
alias dkrps='docker ps --all --format "table {{.ID}}\t{{.Names}}\t{{.Image}}\t{{.Status}}"'

How to know which docker volume connected to your container? 

Let's create a container named as myweb with a docker volume attached as web-volume.

docker run -d --name myweb --mount source=web-volume,destination=/usr/share/nginx/html nginx

Using inspect sub-command on the container --format string with JSON forms is going to return a Json block:

docker container inspect --format '{{json .HostConfig.Mounts}}' myweb |jq

alias knv2c="docker container inspect --format '{{json .HostConfig.Mounts}}' $1"
kn2c myweb|jq

alias k2c="docker container inspect -f '{{json .HostConfig.Mounts }}'"

docker container inspect with -f option json format

How to get a container IP from Docker Host?

Let's create a network as vybhava-net and add couple of containers to it as shown:

docker network create vybhava-net
docker run --net vybhava-net --name nginx -d nginx
# same way create n1, n2, n3 etc.

docker network inspect vybhava-net -f '{{json .Containers}}'|jq
  

Image here shows you the filtered JSON output for containers which are attached to the network 'vybhava-net'

Docker network inspect filtered for containers

How to get the network block and IPAddress of a given container? 

Getting the IPaddress of a container is as follows: 

Let's create an example container name as urweb.

  
docker run -d --name urweb \
--mount source=zing,destination=/usr/share/nginx/html nginx:alpine

Command execution related to alias using shell arguments:

docker container \
  inspect  -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' urweb

alias getip="docker container inspect  -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $1"
getip urweb 

The following is the execution of the alias command for the container within the default network.

How to get the User defined bridge network IPAddress? 

Let's make user defined network as mynet.

  
docker network create mynet; docker network ls

#create a mongo container
docker run -d --rm --name mongodb01 --network mynet  \
-e MONGO_INITDB_ROOT_USERNAME=admin  \
-e MONGO_INITDB_ROOT_PASSWORD="vybhavatechnologies" mongo

#Create a mongo-express container 
docker run -it --rm \
    --network mynet \
    --name mongo-express \
    -p 8081:8081 \
    -e ME_CONFIG_OPTIONS_EDITORTHEME="ambiance" \
    -e ME_CONFIG_MONGODB_SERVER="mongodb01" \
    -e ME_CONFIG_MONGODB_ADMINUSERNAME="admin" \
    -e ME_CONFIG_MONGODB_ADMINPASSWORD="vybhavatechnologies" \
    mongo-express

After adding two containers mongo, mongo-express to the mynet we can inspect the Network settings map to this user defined bridge network.

	
$ docker inspect -f '{{.Name}}-{{.NetworkSettings.Networks.mynet.IPAddress }}' 96bbda65987a
/mongo-express-172.19.0.3
[node1] (local) root@192.168.0.8 ~
$ docker inspect -f '{{.Name}}-{{.NetworkSettings.Networks.mynet.IPAddress }}' e2ba199e8307
/mongodb01-172.19.0.2