Start YB-Masters

AttentionThis page documents an earlier version. Go to the latest (v2.1)version.

NoteFor any cluster, the number of nodes on which the YB-Masters need to be started on must equal the replication factor.

As an example scenario, let us assume the following.

  • We want to create a a 4 node cluster with replication factor 3.
    • We would need to run the YB-Master process on three nodes (node-a, node-b, node-c)
    • Let us assume their IP addresses are 172.151.17.130, 172.151.17.220 and 172.151.17.140
  • We have multiple data drives mounted on /home/centos/disk1, /home/centos/disk2

This section covers deployment for a single region/zone (or a single datacenter/rack). Execute the following steps on each of the instances.

  • Run yb-master binary on each of the nodes as shown below. Note how multiple directories can be provided to the —fs_data_dirs flag. For the full list of flags, see the yb-master Reference.
  1. $ ./bin/yb-master \
  2. --master_addresses 172.151.17.v1.0:7100,172.151.17.220:7100,172.151.17.v1.0:7100 \
  3. --fs_data_dirs "/home/centos/disk1,/home/centos/disk2" \
  4. >& /home/centos/disk1/yb-master.out &
  • Alternatively, you can also create a master.conf file with the following flags and then run the yb-master with the —flagfile option as shown below.
  1. --master_addresses=172.151.17.v1.0:7100,172.151.17.220:7100,172.151.17.v1.0:7100
  2. --fs_data_dirs=/home/centos/disk1,/home/centos/disk2 
  1. $ ./bin/yb-master --flagfile master.conf >& /home/centos/disk1/yb-master.out &
  • Make sure all the 3 yb-masters are now working as expected by inspecting the INFO log. The default logs directory is always inside the first directory specified in the —fs_data_dirs flag.

You can do this as shown below.

  1. $ cat /home/centos/disk1/yb-data/master/logs/yb-master.INFO

You can see that the 3 yb-masters were able to discover each other and were also able to elect a Raft leader among themselves (the remaining two act as Raft followers).

For the masters that become followers, you will see the following line in the log.

  1. I0912 16:11:07.419591  8030 sys_catalog.cc:332] T 00000000000000000000000000000000 P bc42e1c52ffe4419896a816af48226bc [sys.catalog]: This master's current role is: FOLLOWER

For the master that becomes the leader, you will see the following line in the log.

  1. I0912 16:11:06.899287 27220 raft_consensus.cc:738] T 00000000000000000000000000000000 P 21171528d28446c8ac0b1a3f489e8e4b [term 2 LEADER]: Becoming Leader. State: Replica: 21171528d28446c8ac0b1a3f489e8e4b, State: 1, Role: LEADER

TipRemember to add the command with which you launched yb-master to a cron to restart it if it goes down.

Now we are ready to start the yb-tservers.