Design considerations for Docker high availability setup

Clustering is a commonly implemented solution for High Availability in systems, where servers can be clustered to form a fail-over or a load balancing system.

To setup HA in Docker, there are many solutions, the most prominent one being Docker Swarm. Swarm is a tool to create a cluster of Docker hosts and to manage them.

Docker Swarm is integrated into the Docker Engine and it consists of a manager node to manage the cluster and worker nodes to perform various tasks.

Docker Swarm architecture

While it seems like an easy task to setup Docker high availability using Docker Swarm, there are a few crucial decision-making aspects that determines the effectiveness of the HA setup.

1. Initial setup

Having a good high availability design is the most important aspect. While ensuring enough redundancy, the solution must be also cost-effective to avoid resource wastage.

After analyzing the size of the Docker system and the priority of the applications running in each, Bobcares engineers determine the number and type of nodes in the HA system.

Configuring the Swarm master, a backup master node, the Swarm agents and their duplicates, etc. are also included in our initial design and setup for Docker HA.

2. Cluster management

There are several tools such as Shipyard, to manage the Docker Swarm. But the features provided by these UIs are for simpler tasks such as start, stop, resource allotment, etc.

At Bobcares, we use CLI to access the Docker infrastructure for the initial setup and to perform complex routine tasks such as data migration and cluster management.

We also configure shared data volumes to minimize the overhead involved in data migration and to ensure that the updated data is available in all the nodes.

3. Monitoring

Though we configure automated fail-over systems for the cluster, our 24/7 team also monitors the HA system to avoid a failure due to network issues or resource crunch.

At Bobcares, we perform periodic fail-over testing to identify any connectivity issues or anomalies beforehand. This helps us to guarantee 99.9% uptime to our customers.

Periodic maintenance of the Swarm that we perform includes tasks such as image management, resource control based on the usage and vulnerability patching.

To summarize..

As we saw, having a Docker high availability system is indispensable in ensuring high uptime for your businesses hosted in Docker infrastructure.

But configuring a HA system requires expertise and proper planning to ensure that the benefits of the setup are actually reaped in the production environment.

Bobcares engineers set up and manage Docker infrastructure for businesses, which includes custom image management and security updates for the containers.

If you’d like to know how to manage your Docker resources efficiently for your business purpose, we’d be happy to talk to you.