MongoDB Minor Release Upgrade from 3.2.7 to 3.2.13

[Pravin Dwiwedi]

Hi All, I am going to Upgrade a Sharded Cluster Mongodb 3.2.7 to 3.2.13(community edition) on RHEL 6.6 through Ansible. 

As per the Mongodb Doc recommendations --

1> Stop Metadata Changes(any operation which changes the metadata) during the Upgrade

2> Stop Balancer

3> Back up the config Database(Optional)

4> Upgrade the secondary members of the replica set one at a time.

5> Restart the member and wait for the member to recover to SECONDARY state before upgrading the next secondary member.

6> Step down primary using rs.stepDown()

7> Shut down the stepped-down primary and upgrade

8> Restart the stepped-down primary.

9> Upgrade the config servers one at a time in reverse order of the configDB or --configdb setting for the mongos. 

10> Upgrade the mongos instances one by one.

11> Re-enable the balancer.

Does step 9 hold still true for 3.2.7 to 3.2.13?

Or 

we only can follow the steps (4,5,6,7,8) of  shard server up-gradation?

Also, I would appreciate if anyone is having Ansible playbooks for MongoDB upgrade and could share with me. Or any reference for MongoDB upgrade through Ansible.

Regards

Pravin 

[Pravin Dwiwedi]

Any update on this?? Any help would be appreciated..

[Rupa Narayanan]

Pravin,

For any minor release (unless specified), it's a binary replacement since the minor releases are meant to address defects identified and minor improvements.  As a best practice, we recommend maintaining every part of your cluster are using the same version (i.e. config servers, shard servers, and mongos) to minimize any possibility of unforeseen issues.

And you would need to consider these steps for an ansible script. Prior to the upgrade, please make sure to:

- Backup the config server since it contains all the metadata associated with the sharded cluster 

- Review the release notes for all the intermediary minor versions to understand the impact on your deployment

- Test the Ansible script in your test environment 

Also, if you are using SCCC setup for your config server, we recommend upgrading to Config Server as Replica Set (CSRS) since this is the default starting with MongoDB 3.4 and also provides your config servers with all the advantages and guarantees of a replica set.helps with rolling upgrades on the config server.

Regards,

Rupa