Consensus in ASAB Maestro

LogMan.io is a cluster technology. This fact brings high availability and security to the product. However, it also brings higher complexity of the system. Many services and microservices need to communicate among the cluster and share data. We use Apache ZooKeeper as a consensus technology in the distributed system. In ZooKeeper, all services have access to a "common truth" wherever in the cluster they are.

The core of the "common truth" is stored in the /asab node of the ZooKeeper.

/asab content

• /asab/ca - Certificate Authority
• /asab/config - Cluster Configuration
• /asab/docker - stores Docker configuration shared among the cluster, including credentials for Docker registry.
• /asab/nodes - Connected cluster nodes
• /asab/run - data advertised by running ASAB microservices
• /asab/vault - storage of secrets

You might notice that some pieces of information about the cluster overlap. To provide reliable data about the cluster, we use multiple data sources. You might notice multiple service discovery strategies and multi-level monitoring.