K8SSAND-1036 ⁃ Is there any way of changing additional cassandra.yaml parameters ?

[mikekuzak]

Hi All,

When looking though the Helm charts I couldn't find a way to change some additional settings like:

Especially:

• batch_size_warn_threshold_in_kb
• batch_size_fail_threshold_in_kb

But also these:

• counter_write_request_timeout_in_ms
• request_timeout_in_ms
• read_request_timeout_in_ms
• range_request_timeout_in_ms
• write_request_timeout_in_ms

Thanks for any suggestion on how to adjust these.

┆Issue is synchronized with this Jira Task by Unito
┆Reviewer: Michael Burman
┆epic: Advanced Component Configuration
┆fixVersions: k8ssandra-1.4.0
┆friendlyId: K8SSAND-1036
┆priority: Medium

[jdonenine]

Hey @mikekuzak it would be possible to manipulate the CassandraDatacenter resources that get deployed after installation, but you would lose those settings when you upgrade the charts later, so admittedly it's not a perfect answer.

With 1.x we've taken a very opinionated view of directly representing the settings available within the charts. For the k8ssandra-operator we've kicked around a lot the question of if that's the best way to go or should we be able to just dump a blob of configuration in and pass it through. Much more flexible but it then lacks the saftey we might like.

We'd definitely be interested to hear what you think about that tradeoff -- is having access to any and every configuration option more important for you there?

[mikekuzak]

Hi I think access to the cassandra.yaml properties should be provided as a customization form. I default values should still stay as they are, but there are centain scenarios where you want to customize them.

Example:
With 3 Env. (none k8s) we are doing weekly dump and restore from Prod to UAT|QA, having auto_snapshot on is a waist of diskspace and time in this case. The Truncate command creates snapshots . we are talking about 80G per node here.

I understand templating so many options via helm is a nightmare, but more secure that a blob option. The advantage also is you can override only specific values.

[jsanda]

While we are still trying to figure out the best way(s) to expose and manage configs, I do think it is worthwhile to expose some of these settings in the short term. These and other settings have come up before (see #1023). If you want to use K8ssandra for production, it certainly makes sense to want a lot of these properties to be configurable.