Configure SRM for Failover and Failback

Learn how to configure SRM for failover and failback.

To prepare for a failover or failback scenario you have to set up SRM with bidirectional replication. Additionally, you have to make sure that all mission critical topics and consumer groups are whitelisted on both the primary and backup clusters.

In Cloudera Manager select Streams Replication Manager.
Go to Configuration.
Set up bidirectional replication between clusters:

note

The following example contains the minimum required properties only. For a more in-depth configuration example for a cluster setup with bidirectional replication, see Configuration Examples.
1. Find the Streams Replication Manager Cluster alias. property.
2. Add a comma delimited list of cluster aliases. For example:
```
primary, secondary
```
3. Find the streams.replication.manager's replication configs property.
4. Click the add button and add new lines for each cluster alias you have specified in the Streams Replication Manager Cluster alias. property
5. Add connection information for your clusters. For example:
```
primary.bootstrap.servers=primary_host1:9092,primary_host2:9092,primary_host3:9092
secondary.bootstrap.servers=secondary_host1:9092,secondary_host2:9092,secondary_host3:9092
```
  Each cluster has to be added to a new line. If a cluster has multiple hosts, add them to the same line but delimit them with commas.
6. Click the add button and add new lines for each unique replication you want to add and enable.
7. Add and enable your replications. For example:
```
primary->secondary.enabled=true
secondary->primary.enabled=true
```

Whitelist required consumer groups and topics on the primary cluster.

Whitelist groups:

srm-control groups --source [PRIMARY_CLUSTER] --target [SECONDARY_CLUSTER] --add [GROUP1],[GROUP2]

Whitelist topics:

srm-control topics --source [PRIMARY_CLUSTER] --target [SECONDARY_CLUSTER] --add [TOPIC1],[TOPIC2]

Whitelist required remote topics and consumer groups on the secondary cluster.

important

If remote topics and consumer groups are not whitelisted on the secondary cluster, a failback operation will be impossible to carry out.
1. Whitelist remote groups:
```
srm-control groups --source [SECONDARY_CLUSTER] --target [PRIMARY_CLUSTER] --add [GROUP1],[GROUP2]
```
2. Whitelist remote topics:
```
srm-control topics --source [SECONDARY_CLUSTER] --target [PRIMARY_CLUSTER] --add [PRIMARY_CLUSTER.TOPIC1],[PRIMARY_CLUSTER.TOPIC2]
```

Verify that all required topics and consumer groups are whitelisted.

Verify consumer groups:

srm-control groups --source [PRIMARY_CLUSTER] --target [SECONDARY_CLUSTER] --list

srm-control groups --source [SECONDARY_CLUSTER] --target [PRIMARY_CLUSTER] --list

Verify topics:

srm-control topics --source [PRIMARY_CLUSTER] --target [SECONDARY_CLUSTER] --list

srm-control topics --source [SECONDARY_CLUSTER] --target [PRIMARY_CLUSTER] --list

SRM is set up with bidirectional replication and all mission critical topics and consumer groups are whitelisted on both the primary and secondary clusters.