syncobj_admin

syncobj_admin is utility for monitoring cluster state and adding / removing cluster nodes. It is installed with PySyncObj from pip. It has folowing modes:

Status

You can check each node status with folowing command:

syncobj_admin -conn localhost:1180 -status

You'll get different node parameters. Most usefull are:

• state - it can be one of the folowing:

   0 - folower
   1 - candidate
   2 - leader

• leader - current cluster leader
• partner_nodes_count - number of partner nodes
• partner_node_status - statuses of connections to partner nodes:

   0 - disconnected
   1 - connecting
   2 - connected

• commit_idx - last commited transaction number
• last_applied - last applied transaction number
• version - version of a library
• revision - previous git commit hash
• uptime - number of seconds that node process is alive

Add new node

• Step 1: Add node with:

syncobj_admin -conn localhost:1180 -add localhost:1181

localhost:1180 is one of the existing cluster nodes, and localhost:1181 is the node you want to add.

• Step 2: Turn new node on. Pass ALL current cluster nodes to a new node (currently it could not detect cluster configuration automatically)

In case of switching from 1-node cluster to 2-node cluster, you don't need to wait untill syncobj_admin confirm - you will see confirmation as soon as you enable new node.

Remove existing node

• Step 1: Turn existing node off
• Step 2: Remove node with:

syncobj_admin -conn localhost:1180 -remove localhost:1181

localhost:1180 is one of the nodes left in cluster, and localhost:1181 is the node you want to remove.