Configure Portainer Web UI for Docker on CentOS 7

Portainer is a web-based user interface for management of Docker environments. Portainer is free and open-source management toolset that allows us to easily build, manage and maintain Docker environments. Portainer gives us a detailed overview of our Docker environments and allows us to manage our containers, images, networks, volumes, registries, services, nodes and stacks from a single web interface.

Requirement of a Web UI arises because Docker Engine CE provides a single CLI utility (i.e. docker) to create and manage all components of the Docker environments. It is good for hardcore CLI DevOps engineers, but it is quiet difficult for GUI addicts. Therefore, we have to look for some third party Web UI like Portainer to help the non-CLI users in performing the same Docker tasks from an Web UI.

In this article, we are configuring a Docker Web UI, i.e. Portainer on CentOS 7 based Docker Swarm. To achieve this we use the Docker technology, as we download Portainer image from Docker Hub and run it to manage our Docker Swarm cluster.

There is a good book on Docker Technology i.e. Docker Deep Dive. We highly recommend you to read it for in-depth understanding of Docker Technology.

System Specification:

We have a Docker Swarm cluster on CentOS 7 consist of two nodes (1 Manager & 1 Worker) with following specifications:

Hostname:	docker-manager-01	docker-worker-01
IP Address:	192.168.116.150/24	192.168.116.151/24
Operating System:	CentOS 7.6	CentOS 7.6
Docker Version:	Docker CE 18.09	Docker CE 18.09
Node Role:	Manager	Worker

To setup the required environment, you can refer to our previous article Configure Docker Swarm Cluster on CentOS 7.

Configuring Portainer Web UI for Docker on CentOS 7:

Connect to Docker Swarm's Manager node docker-manager-01 using ssh as root user.

List the nodes in our Docker Swarm cluster.

[root@docker-manager-01 ~]# docker node ls
ID                            HOSTNAME                        STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
3b9wynaya1wu910nf01m5jeeq *   docker-manager-01.example.com   Ready               Active              Leader              18.09.3
ydgqdyoksx2mb0snhe1hwvco7     docker-worker-01.example.com    Ready               Active

Pull the latest Portainer image from Portainer repository at Docker Hub.

[root@docker-manager-01 ~]# docker pull portainer/portainer:latest
latest: Pulling from portainer/portainer
d1e017099d17: Pull complete
0b1e707a06d2: Pull complete
Digest: sha256:d6cc2c20c0af38d8d557ab994c419c799a10fe825e4aa57fea2e2e507a13747d
Status: Downloaded newer image for portainer/portainer:latest

Create a Docker volume for Portainer container data.

[root@docker-manager-01 ~]# docker volume create portainer_data
portainer_data

Create and run a Docker container from Portainer image.

[root@docker-manager-01 ~]# docker run -d \
> --name portainer-01 \
> --restart unless-stopped \
> -p 9000:9000 \
> -v /var/run/docker.sock:/var/run/docker.sock \
> -v portainer_data:/data \
> portainer/portainer
41feb52e01f51a6a2c65841c24d00c2ca9b456441dd78367bb9d8dda33c5d9c4

We mounted the Docker volume portainer_data in portainer1 container and published the service port 9000.

By publishing the service port 9000, we have mapped it with the service port 9000 of Docker host. Therefore, we have to allow this service port in Docker host's firewall.

[root@docker-manager-01 ~]# firewall-cmd --permanent --add-port=9000/tcp
success
[root@docker-manager-01 ~]# firewall-cmd --reload
success

Browse URL https://docker-manager-01.example.com:9000/ and create Portainer’s initial admin account.

Note: If you do not create a Portainer admin account within 5 minutes after starting the portainer1 container. The container will be stopped automatically and then you have to start it again.