Cluster Initialization in Platform9 Managed Kubernetes (PMK)

![clusters_and_containervisors_view.png](https://lh3.googleusercontent.com/Tn67P9fhhPqCNF6xYl6mfVehG8AtLcLOM0NMW3YukBkWB5cSpYofkLQo1vrqsZiDBON05GC4ZQwWgEV9YBdoNA6Hzy_loS0cvT3BzkxmLesk6UsX_xugsrGppJD-Mc8fjHIF2QrU) **Cluster initialization** The first time one or more nodes are attached to a cluster, PMK configures the nodes to form a complete Kubernetes cluster. Currently, PMK automatically decides the number and placement of Master and Worker nodes. In the future, PMK will give administrators an “advanced mode” option allowing them to override and customize those decisions. Through the CM server, PMK then sends to each node a configuration and a set of scripts to initialize each node according to the configuration. This includes installing or upgrading Docker to the required version; starting 2 docker daemons (bootstrap and main), creating the etcd K/V store, establishing the flannel network layer, starting kubelet, and running the Kubernetes appropriate for the node’s role (master vs. worker). The following diagram shows the component layout of a fully formed cluster. ![architecture.png](https://lh6.googleusercontent.com/ZQZoFL6tDpkiberG_X1CREitwNIDCHnRajnOlJqByU-4HzRQi1RRoDlGj7pGRaqD2a7Yg4xBwQx7oHp_mR8ie96O5w_KMT84av-JMsPMHXeoBpVYn3iJKeGZkWG4q0J06OZMuLIe)

When nodes are first attached to a cluster, PMK configures them to form a Kubernetes cluster. It automatically decides the number and placement of Master and Worker nodes, with future plans to allow administrators to customize these decisions. PMK uses a configuration and scripts sent via the CM server to initialize each node, including installing Docker, starting Docker daemons, creating the etcd K/V store, establishing the flannel network layer, starting kubelet, and running Kubernetes components appropriate for the node's role.