Introduction
In this post I would like to share how to create a Docker Cluster with Swarm on the new VMware Project Photon.
Project Photon is an open source Linux container host which is optimized for running on VMware vSphere. It has a very small footprint, is extensible and supports the most common container formats including Docker, Rocket and Garden. You can find more information about Photon at the VMware GitHub site.
Docker Swarm is native clustering for Docker. It allows you create and access to a pool of Docker hosts using the full suite of Docker tools. Because Docker Swarm serves the standard Docker API, any tool that already communicates with a Docker daemon can use Swarm to transparently scale to multiple hosts.
Without Docker Swarm you are managing each Docker host with a separate CLI session.
Docker without Swarm with separate CLI sessions.
With Docker Swarm you are able to manage Docker images on a cluster of Docker hosts with one CLI with the standard Docker API.
Docker on Photon managed with Swarm.
Photon Configuration
In my Lab Environment I deployed four Photon VM’s. One for managing the Docker Swarm Cluster and three for the cluster nodes.
Installing Photon on new VM’s is very easy and is well documented by VMware, which you can find here.
Again the footprint of Photon is very small (384 MB Memory) and the installation is very quick. You have a running VM in a couple of minutes.
When the VM’s were created I needed to configure a static IP-address since Photon is configured for DHCP by default.
root [ ~ ]# mv /etc/systemd/network/10-dhcp-eth0.network /etc/systemd/network/10-static-eth0.network
My configuration example:
[Match] Name=eth0 [Network] Address=192.168.20.104/24 Gateway=192.168.20.254</code> DNS=192.168.20.1</code> Domains=cloudxtreme.local
Restart the network.
root [ ~ ]# systemctl restart systemd-networkd.service
In this lab I did enable SSH for the root user.
root [ ~ ]# sed -i 's/PermitRootLogin no/PermitRootLogin yes/g' /etc/ssh/sshd_config root [ ~ ]# systemctl restart sshd
Docker Swarm Configuration
1. SSH to each node of the cluster. Stop the Docker service and let Docker listen to incoming requests.
root [ ~ ]# systemctl stop docker.service root [ ~ ]# docker -d -H tcp://0.0.0.0:2375
2. SSH to the Swarm Cluster Management VM and create the new Cluster
root [ ~ ]# docker run --rm swarm create
This command will return a Cluster ID token
e1043c50cb84447d41de500527c04ebd
3. Now we run an agent for each Cluster Node.
docker run -d swarm join --addr=<node_ip>:2375 token://<cluster_id>
So in my running configuration:
root [ ~ ]# docker run -d swarm join --addr=192.168.20.104:2375 token://e1043c50cb84447d41de500527c0
4. Create the Swarm Manager in your Management VM.
root [ ~ ]# run docker run -t -P swarm manage
The Swarm Manager starts with a random TCP port. To find out which one run the command
docker ps
root [ ~ ]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES ec38592a23e7 swarm:0.2.0 "/swarm join --addr= 8 minutes ago Up 8 minutes 2375/tcp sharp_sinoussi 7bdea87b7885 swarm:0.2.0 "/swarm manage token 4 days ago Up 4 days 0.0.0.0:49153->2375/tcp prickly_yalow c4ad29b34582 swarm:0.2.0 "/swarm join --addr= 4 days ago Up 4 days 2375/tcp tender_hoover 59352a434d72 swarm:0.2.0 "/swarm join --addr= 4 days ago Up 4 days 2375/tcp grave_poitras cde216a6aa59 swarm:0.2.0 "/swarm join --addr= 4 days ago Up 4 days 2375/tcp grave_payne<code>
In my configuration it runs on TCP port 49153
5. Command to list the registered agents.
root [ ~ ]# docker run --rm swarm list token://e1043c50cb84447d41de500527c04ebd 192.168.20.103:2375 192.168.20.104:2375 192.168.20.102:2375
6. The Docker Swarm Cluster setup is done. We can use all Docker commands in the cluster.
7. List the status of the Docker Swarm Cluster
root [ ~ ]# docker -H tcp://localhost:49153 info Containers: 0 Strategy: spread Filters: affinity, health, constraint, port, dependency Nodes: 3 electron: 192.168.20.102:2375 └ Containers: 0 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB neutron: 192.168.20.103:2375 └ Containers: 0 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB proton: 192.168.20.104:2375 └ Containers: 0 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB
8. Example to run a new Docker container:
root [ ~ ]# docker run -d -it --name wordpress -h wordpress -p 80:80 -p 443:443 appcontainers/wordpress
9. List of the current containers (note the VM hostname in the name of NAMES column of the container):
root [ ~ ]# docker -H tcp://0.0.0.0:49153 ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c2df483f526a appcontainers/wordpress:latest "/bin/sh -c /bin/bas 3 minutes ago Up 2 minutes 3306/tcp, 192.168.20.104:80->80/tcp, 192.168.20.104:443->443/tcp proton/wordpress 6b7792daf85d centos:6 "/bin/bash" 14 minutes ago Exited (0) 14 minutes ago electron/stoic_fermi f8c652bfb18b wordpress:4 "/entrypoint.sh apac 23 minutes ago Exited (1) 21 minutes ago proton/nostalgic_hawking 7f101ceb9965 appcontainers/wordpress:latest "/bin/sh -c /bin/bas 30 minutes ago electron/goofy_colden 34b942afaef8 appcontainers/wordpress:latest "/bin/sh -c /bin/bas 35 minutes ago
10. List the current status of the Swarm Cluster
root [ ~ ]# docker -H tcp://0.0.0.0:49153 info Containers: 5 Strategy: spread Filters: affinity, health, constraint, port, dependency Nodes: 3 electron: 192.168.20.102:2375 └ Containers: 2 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB neutron: 192.168.20.103:2375 └ Containers: 1 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB proton: 192.168.20.104:2375 └ Containers: 2 └ Reserved CPUs: 0 / 2 └ Reserved Memory: 0 B / 381.9 MiB
Conclusion
Photon, with it’s small footprint, is lean, fast and perfect for Docker containers on VMware infrastructure. With Photon, Docker and Swarm it is easy to out scale your Docker environment on your VMware infrastructure.
