Docker Registry: A repository of images. Registries are public or private that contain images for download. Some registries allow users to upload images to make them available to others
Dockerfile: A configuration file with build instructions for Docker image.Dockerfile automate the steps for image customization.
As we discussed two types of registry are available:
Public Docker Registry: Users just want to explore or want a in-build solution. They can use hosted docker registries. Docker hub is the example of public registry where user can host the registry.
Private Docker Registry: Lot of organization have security concern for public docker registry. They want to manage and store the customize image, only want to share in the organization can go for private docker registry.
Note: In this post, I will be configuring the private docker registry.
cat /etc/centos-release
CentOS Linux release 7.2.1511 (Core)
Installing docker-registry
yum install docker-registry
//Docker Registry Configuration file :rpm -ql under etc directory [root@localhost amit]# rpm -ql docker-registry-0.9.1-7.el7.x86_64
/etc/docker-registry.yml
/etc/sysconfig/docker-registry
//Docker Registry default image store location
Cat /etc/docker-registry.yml
local: &local
<<: *common
storage: local
storage_path: _env:STORAGE_PATH:/var/lib/docker-registry
//Enable and start the docker registry and default port is 5000: systemctl enable docker-registry systemctl start docker-registry
systemctl status docker-registry docker-registry.service - Registry server for Docker Loaded: loaded (/usr/lib/systemd/system/docker-registry.service; enabled; vendor preset: disabled) Active: active (running) since Tue 2017-01-24 13:21:37 IST; 55s ago Main PID: 24323 (gunicorn) Memory: 162.8M CGroup: /system.slice/docker-registry.service netstat -tupln|grep 5000 tcp 0 0 0.0.0.0:5000 0.0.0.0:* LISTEN 24323/python
Docker registry is running on one of the host node, It need to be accessed by other nodes for uploading/downloading the images.
On the client node which need access the private registry need to modify /etc/sysconfig/docker
DOCKER_OPTS=”–insecure-registry localhost:5000″
link: https://docs.docker.com/registry/insecure/
//tag and push the image to docker registry
docker tag <image id> <ip of docker registry>:5000/<name>:<tag>
docker push <ip of docker registry>:5000/<name>:<tag>
docker tag ff6f0851ef57 localhost:5000/jenkinslocal:latest
docker push localhost:5000/jenkinslocal:latest
The push refers to a repository [localhost:5000/jenkinslocal]
7fef8c44bf7f: Image successfully pushed
971a0fc79a1a: Image successfully pushed
5b8b7745040c: Image successfully pushed
7d114ad7e1fe: Image successfully pushed
5b848d38b406: Image successfully pushed
4e87708e08e8: Image successfully pushed
d458e9b86b04: Image successfully pushed
ca787184f0ab: Image successfully pushed
4238f6371816: Image successfully pushed
a2eea3e16ec7: Image successfully pushed
1f764d32a220: Image successfully pushed
1af14ac896ef: Image successfully pushed
a7afeb77f416: Image successfully pushed
cef349a9d76f: Image successfully pushed
1d16eb83eef5: Image successfully pushed
dfe1af64a72d: Image successfully pushed
9f17712cba0b: Image successfully pushed
223c0d04a137: Image successfully pushed
fe4c16cbf7a4: Image successfully pushed
Pushing tag for rev [ff6f0851ef57] on {http://localhost:5000/v1/repositories/jenkinslocal/tags/latest}