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199 lines
4.4 KiB
199 lines
4.4 KiB
= Services Admin
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== Displaying Docker Images
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To see the list of Docker images on the system, you can issue the following command.
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[source,sh]
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----
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docker images
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----
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This command is used to display all the images currently installed on the system.
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**Output:**
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- TAG − This is used to logically tag images.
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- Image ID − This is used to uniquely identify the image.
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- Created − The number of days since the image was created.
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- Virtual Size − The size of the image.
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== Removing Docker Images
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The Docker images on the system can be removed via the docker rmi command.
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[source,sh]
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----
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docker rmi
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This command is used to remove Docker images.
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Syntax
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docker rmi ImageID
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----
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== Containers
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Containers are instances of Docker images that can be run using the Docker run command. The basic purpose of Docker is to run containers.
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=== Running a Container
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Running of containers is managed with the Docker run command. To run a container in an interactive mode, first launch the Docker container.
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[source,sh]
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----
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docker run –it myimage /bin/bash
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----
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=== Listing of Containers
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One can list all of the containers on the machine via the docker ps command. This command is used to return the currently running containers.
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[source,sh]
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----
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docker ps
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----
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=== Display the running processes of a container
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With this command, you can see the top processes within a container.
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Syntax
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[source,sh]
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----
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docker top ContainerID
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Options
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ContainerID − This is the Container ID for which you want to see the top processes.
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----
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=== Stop a running container
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This command is used to stop a running container.
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[source,sh]
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----
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docker stop ContainerID
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Options
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ContainerID − This is the Container ID which needs to be stopped.
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----
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=== Attach a running container
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This command is used to attach to a running container.
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[source,sh]
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docker attach ContainerID
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Options
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ContainerID − This is the Container ID to which you need to attach.
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----
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=== Delete container
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This command is used to delete a container.
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[source,sh]
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docker rm ContainerID
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Options
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ContainerID − This is the Container ID which needs to be removed.
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----
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=== Container Logging
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Logging is also available at the container level.
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[source,sh]
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Docker logs containerID
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Parameters
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containerID − This is the ID of the container for which you need to see the logs.
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----
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== Volumes
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Volumes are the preferred mechanism for persisting data generated by and used by Docker containers.
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[source,sh]
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docker run -d --name mycontainer -v /var/www/html:/var/html nginx:latest
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----
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== repositories
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You might have the need to have your own private repositories. You may not want to host the repositories on Docker Hub. For this, there is a repository container itself from Docker. Let’s see how we can download and use the container for registry.
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=== Create
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[source,sh]
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docker run –d –p 5000:5000 –-name registry registry:2
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The following points need to be noted about the above command:
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Registry is the container managed by Docker which can be used to host private repositories.
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The port number exposed by the container is 5000. Hence with the –p command, we are mapping the same port number to the 5000 port number on our localhost.
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We are just tagging the registry container as “2”, to differentiate it on the Docker host.
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The –d option is used to run the container in detached mode. This is so that the container can run in the background
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----
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== Docker Hub
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Docker Hub is a registry service on the cloud that allows you to download Docker images that are built by other communities. You can also upload your own Docker built images to Docker hub.
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To run apache, you need to run the following command:
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[source,sh]
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docker run -p 8080:80 apache
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Note the following points about the above command −
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Here, apache is the name of the image we want to download from Docker hub and install on our Ubuntu machine.
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-p is used to map the port number of the internal Docker image to our main Ubuntu server so that we can access the container accordingly.
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----
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=== Push
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use the Docker push command to push the image to our private repository.
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[source,sh]
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docker push localhost:5000/myimage
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----
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=== Pull
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use the following Docker pull command to pull image from our private repository.
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[source,sh]
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docker pull localhost:5000/myimage
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----
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