Docker 1.11 installation and run on CentOS7: configure and use the local repository: Docker Repository image as your local repository

Docker 1.11 installation and run on CentOS7: configure and use the local repository:

Docker registry should be run with the TLS and other security enabled. This only talks on having the local registry up for use leveraging the docker regsitry container serving the docker registry to be local.

Get the Docker repo configured for YUM 

$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'

[dockerrepo]

name=Docker Repository

baseurl=https://yum.dockerproject.org/repo/main/centos/7/

enabled=1

gpgcheck=1

gpgkey=https://yum.dockerproject.org/gpg

EOF

yum clean all

yum repolist

yum -y install docker-engine

# Confirm the docker engine RPMs are installed

[root@compute1 ~]# rpm -qa | grep -i docker

docker-engine-selinux-1.11.2-1.el7.centos.noarch

docker-engine-1.11.2-1.el7.centos.x86_64

[root@compute1 ~]#

Start the docker service and optionally enable the autostart. 

systemctl start docker.service

systemctl status docker.service

systemctl enable docker.service

## Check if the docker service is working fine

Try pulling any image from docker registry and run 

docker -it run centos:latest "/bin/bash"

# download the latest image for registry from the docker hub (you can pull and run or can directly run as the run will pull it for the first time from the docker hub)

docker pull registry 

[root@compute1 yum.repos.d]# docker pull registry

Using default tag: latest

latest: Pulling from library/registry

8387d9ff0016: Pull complete

3b52deaaf0ed: Pull complete

4bd501fad6de: Pull complete

a3ed95caeb02: Pull complete

1d4dc7bffbb8: Pull complete

7c4baf947271: Pull complete

e14b922ad4f5: Pull complete

f1d1dbdd4f97: Pull complete

f2bbca3948d0: Pull complete

4e3899dc28fa: Pull complete

Digest: sha256:f374c0d9b59e6fdf9f8922d59e946b05fbeabaed70b0639d7b6b524f3299e87b

Status: Downloaded newer image for registry:latest

# See all the downloaded docker images

[root@compute1 yum.repos.d]# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED                  SIZE

centos              latest              50dae1ee8677        Less than a second ago   196.7 MB

registry            2                   8ff6a4aae657        4 weeks ago              171.5 MB

registry            latest              bca04f698ba8        5 months ago             422.8 MB

[root@compute1 yum.repos.d]#

# Start of the docker container for the registry, we will start with the option as restart always.

docker run -d -p 5000:5000 --restart=always --name=localregistry registry:2

# confirm that the registry container is up

docker ps

[root@compute1 yum.repos.d]# docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES

01057f771545        registry:2          "/bin/registry serve "   12 minutes ago      Up 12 minutes       0.0.0.0:5000->5000/tcp   localregistry

[root@compute1 yum.repos.d]#

# push the CentOS image to the local registry

# tag the image first to be pushed to the local registry

docker tag centos localhost:5000/centos

# confirm the tag has been given

docker images

[root@compute1 yum.repos.d]# docker images

REPOSITORY              TAG                 IMAGE ID            CREATED                  SIZE

centos                  latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos   latest              50dae1ee8677        Less than a second ago   196.7 MB

registry                2                   8ff6a4aae657        4 weeks ago              171.5 MB

registry                latest              bca04f698ba8        5 months ago             422.8 MB

[root@compute1 yum.repos.d]#

# upload the tagged image now to local image repository

docker push localhost:5000/centos

[root@compute1 yum.repos.d]# docker push localhost:5000/centos

The push refers to a repository [localhost:5000/centos]

0fe55794a0f7: Pushed

latest: digest: sha256:e513d34ffa01c803fc812a479303fe0a4c14673f84301b877bec060578865f1b size: 529

# you can see that the push happens to the local repository reference

# Pull the image from the local repository

docker pull localhost:5000/centos

[root@compute1 yum.repos.d]# docker push localhost:5000/centos

The push refers to a repository [localhost:5000/centos]

0fe55794a0f7: Layer already exists

latest: digest: sha256:7b754086d2c7d74ac39dc0a2545d7b06d4266f873d502feb5b3e8bfca27c5dd8 size: 507

[root@compute1 yum.repos.d]#

As this images is already there in the local repo it says already present

# Start the container with the image which you have in the local registry

docker run localhost:5000/centos "/bin/bash" -it

# Lets make some changes inside the container, I will install httpd in there from the CENTOS repos

[root@compute1 yum.repos.d]# docker run -it localhost:5000/centos "/bin/bash"

[root@dc110984e8f0 /]#

[root@dc110984e8f0 /]#

[root@dc110984e8f0 /]# yum install httpd

[root@dc110984e8f0 etc]# rpm -qa | grep -i http

httpd-tools-2.4.6-40.el7.centos.4.x86_64

httpd-2.4.6-40.el7.centos.4.x86_64

[root@dc110984e8f0 etc]#

[root@dc110984e8f0 etc]#

[root@dc110984e8f0 etc]#

# open another session to the docker host and commit on the running container after the installation of httpd

# from other terminal

docker ps

[root@compute1 ~]# docker ps

CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS              PORTS                    NAMES

8c5bcba48f2d        localhost:5000/centos   "/bin/bash"              3 minutes ago       Up 3 minutes                                 distracted_blackwell

01057f771545        registry:2              "/bin/registry serve "   38 minutes ago      Up 38 minutes       0.0.0.0:5000->5000/tcp   localregistry

[root@compute1 ~]#

# Commit the changes to the container image (install of HTTP is a change to the base image of the container). Committing saves the current state of the container into a new image with the changes. Also the changes are in the form of layered FS on top of the base layer.

[root@compute1 ~]# docker commit 8c5bcba48f2d localhost:5000/centos_with_test_http_install

sha256:9e047acbf61557af27e84054042d8d6f4d58202b9c27db8b9372c49e41d81892

[root@compute1 ~]#

[root@compute1 ~]#

[root@compute1 ~]#

# confirm this is seen as an image

docker images

[root@compute1 ~]# docker images

REPOSITORY                                     TAG                 IMAGE ID            CREATED                  SIZE

centos                                         latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos                          latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos_with_test_http_install   latest              9e047acbf615        54 seconds ago           316.8 MB

registry                                       2                   8ff6a4aae657        4 weeks ago              171.5 MB

registry                                       latest              bca04f698ba8        5 months ago             422.8 MB

[root@compute1 ~]#

# stop the container and delete the images localhost:5000/centos

This deletes the base image as we plan to use the image which we have installed HTTPD on the base image.

[root@compute1 ~]# docker ps

CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS              PORTS                    NAMES

8c5bcba48f2d        localhost:5000/centos   "/bin/bash"              12 minutes ago      Up 12 minutes                                distracted_blackwell

01057f771545        registry:2              "/bin/registry serve "   47 minutes ago      Up 47 minutes       0.0.0.0:5000->5000/tcp   localregistry

# Stopping the container which is running the CentOS with Apache but has come from CentOS Local Repository

[root@compute1 ~]# docker stop 8c5bcba48f2d

8c5bcba48f2d

[root@compute1 ~]#

[root@compute1 ~]#

# Ensure the container is stopped

[root@compute1 ~]# docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES

01057f771545        registry:2          "/bin/registry serve "   47 minutes ago      Up 47 minutes       0.0.0.0:5000->5000/tcp   localregistry

[root@compute1 ~]#

[root@compute1 ~]#

# Remove the local image with the name localhost:5000/centos

[root@compute1 ~]# docker images

REPOSITORY                                     TAG                 IMAGE ID            CREATED                  SIZE

centos                                         latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos                          latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos_with_test_http_install   latest              9e047acbf615        2 minutes ago            316.8 MB

registry                                       2                   8ff6a4aae657        4 weeks ago              171.5 MB

registry                                       latest              bca04f698ba8        5 months ago             422.8 MB

[root@compute1 ~]# docker rmi localhost:5000/centos

Untagged: localhost:5000/centos:latest

[root@compute1 ~]#

[root@compute1 ~]#

# Ensure the image is gone

[root@compute1 ~]# docker images

REPOSITORY                                     TAG                 IMAGE ID            CREATED                  SIZE

centos                                         latest              50dae1ee8677        Less than a second ago   196.7 MB

localhost:5000/centos_with_test_http_install   latest              9e047acbf615        2 minutes ago            316.8 MB

registry                                       2                   8ff6a4aae657        4 weeks ago              171.5 MB

registry                                       latest              bca04f698ba8        5 months ago             422.8 MB

[root@compute1 ~]#

# Spin a container from the available image which has the base centos with httpd installation

[root@compute1 yum.repos.d]# docker run localhost:5000/centos_with_test_http_install  "/bin/bash"

[root@compute1 yum.repos.d]# docker run -it localhost:5000/centos_with_test_http_install "/bin/bash"

[root@f3bcbb08427a /]#

[root@f3bcbb08427a /]#

[root@f3bcbb08427a /]# rpm -qa | grep -i http

httpd-tools-2.4.6-40.el7.centos.4.x86_64

httpd-2.4.6-40.el7.centos.4.x86_64

[root@f3bcbb08427a /]#

# so you can see you have the container with the test apache.