Adding Active Witnesses to an Existing Deployment

To add active witnesses to an existing deployment, use tpm to update the configuration, adding the list of active witnesses and the list of all members within the updated dataservice configuration.

Active Witness hosts must have been prepared using the notes provided in "Installation Prerequisites". Active witnesses must be able to resolve the hostnames of the other managers and hosts in the dataservice. Installation will fail if prerequisities and host availability and stability cannot be confirmed.

Update the /etc/tungsten/tungsten.ini configuration file adding the new host to the list of members, adding the host against the witnesses option and enabling the enable-active-witnesses option. An example is shown below:

Example tungsten.ini

[alpha]
members=host1,host2,host3
witnesses=host3
enable-active-witnesses=true

Show argument definitions

members=host1,host2,host3Hostnames for the dataservice members.

witnesses=host3Witness hosts for the dataservice. Must be provided if enable-active-witnesses is enabled.

enable-active-witnesses=trueEnable active witness hosts.

If your connectors are on the same host as the managers, using the --no-connectors option updates the current deployment without restarting the connectors.

Once installation has completed successfully, and the manager service has started on each configured active witness, the status can be determined using ls within cctrl:

[LOGICAL] /alpha > ls                  

COORDINATOR[host1:AUTOMATIC:ONLINE]

ROUTERS:
+----------------------------------------------------------------------------+
|connector@host1[20446](ONLINE, created=0, active=0)                         |
|connector@host2[21698](ONLINE, created=0, active=0)                         |
|connector@host3[30354](ONLINE, created=0, active=0)                         |
+----------------------------------------------------------------------------+

DATASOURCES:
+----------------------------------------------------------------------------+
|host1(master:ONLINE, progress=8946, THL latency=0.331)                      |
|STATUS [OK] [2018/12/05 04:27:47 PM GMT]                                    |
+----------------------------------------------------------------------------+
|  MANAGER(state=ONLINE)                                                     |
|  REPLICATOR(role=master, state=ONLINE)                                     |
|  DATASERVER(state=ONLINE)                                                  |
|  CONNECTIONS(created=0, active=0)                                          |
+----------------------------------------------------------------------------+

+----------------------------------------------------------------------------+
|host2(slave:ONLINE, progress=8946, latency=0.334)                           |
|STATUS [OK] [2018/12/05 04:06:59 PM GMT]                                    |
+----------------------------------------------------------------------------+
|  MANAGER(state=ONLINE)                                                     |
|  REPLICATOR(role=slave, master=host1, state=ONLINE)                        |
|  DATASERVER(state=ONLINE)                                                  |
|  CONNECTIONS(created=0, active=0)                                          |
+----------------------------------------------------------------------------+

WITNESSES:
+----------------------------------------------------------------------------+
|host3(witness:ONLINE)                                                       |
+----------------------------------------------------------------------------+
|  MANAGER(state=ONLINE)                                                     |
+----------------------------------------------------------------------------+

Validation of the cluster with the new witnesses can be verified by using the cluster validate command within cctrl.