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From John Sanda <john.sa...@gmail.com>
Subject Re: Cassandra on Kubernetes
Date Wed, 30 Oct 2019 20:33:46 GMT
One of the problems I have experienced in the past has more to do with Java
than Cassandra in particular, and that is the JVM ignoring cgroups. With
Cassandra in particular I would often see memory usage go higher than what
was desired. This would lead to pods getting oom killed. This was fixed in
Java 10 though, and I believe even back ported to Java 8.

I think another issue is the lack of options for backup/restore.

I worked with Cassandra in Kubernetes pre-StatefulSets. That was a bit
rough :)

Local volumes were promoted to GA in Kubernetes 1.14. That is certainly a
good thing for stateful applications like Cassandra.

It is also important to have a sufficiently large value for the termination
grace period on pods to allow drain operation to complete, assuming you
perform a drain on shutdown.

On Wed, Oct 30, 2019 at 1:46 PM Akshit Jain <jainakshit95@gmail.com> wrote:

> Hi Jean
> Thanks for replying. I had seen CassKop and the amount functionality it
> provides is quite awesome as compared to other operators.
>
> I would like to know how stable is kubernetes for stateful/database
> applications right now?
>
> I haven't read/heard any major production stateful application running on
> k8s.
>
>
> -Akshit
>
>
>
>
> On Wed, 30 Oct, 2019, 8:12 PM Jean-Armel Luce, <jaluce06@gmail.com> wrote:
>
>> Hi,
>>
>> We are currently developping CassKop, a Cassandra operator for K8S.
>> This operator is developped in Go, based on the operator-sdk framework.
>>
>> At this time of the project, the goal is to deploy a Cassandra cluster in
>> 1 Kubernetes datacenter, but this will change in next versions to deal with
>> Kubernetes in multi-datacenters.
>>
>> The following features are already supported by CassKop:
>> - Deployment of a C* cluster (rack or AZ aware)
>> - Scaling up the cluster (with cleanup)
>> - Scaling down the cluster (with decommission prior to Kubernetes scale
>> down)
>> - Pods operations (removenode, upgradesstable, cleanup, rebuild..)
>> - Adding a Cassandra DC
>> - Removing a Cassandra DC
>> - Setting and modifying configuration files
>> - Setting and modifying configuration parameters
>> - Update of the Cassandra docker image
>> - Rolling update of a Cassandra cluster
>> - Update of Cassandra version (including upgradesstable in case of major
>> upgrade)
>> - Update of JVM
>> - Update of configuration
>> - Stopping a Kubernetes node for maintenance
>> - Process a remove node (and create new Cassandra node on another
>> Kubernetes node)
>> - Process a replace address (of the old Cassandra node on another
>> Kubernetes node)
>> - Manage operations on pods through CassKop plugin (cleanup, rebuild,
>> upgradesstable, removenode..)
>> - Monitoring (using Instaclustr Prometheus exporter to Prometheus/Grafana)
>> - Pause/Restart & rolling restart operations through CassKoP plugin.
>>
>> We use also Cassandra reaper for scheduling repair sessions.
>>
>>
>> If you would like more informations about this operator, you may have a
>> look here : https://github.com/Orange-OpenSource/cassandra-k8s-operator
>>
>> Please, feel free to download it and try it. We would be more than happy
>> to receive your feedback
>>
>>
>> If you have any question about this operator, feel free to contact us via
>> our mailing-list: prj.casskop.support@list.orangeportails.net or on our
>> slack https://casskop.slack.com
>>
>> Note : this operator is still in alpha version and works only in a mono
>> region architecture for now. We are currently working hard for adding new
>> features in order to run it in multi-regions architecture.
>>
>>
>> Thanks.
>>
>>
>>
>> Le mer. 30 oct. 2019 à 13:56, Akshit Jain <jainakshit95@gmail.com> a
>> écrit :
>>
>>> Hi everyone,
>>>
>>> Is there anyone who is running Cassandra on K8s clusters. It would be
>>> great if you can share your experience , the operator you are using and the
>>> overall stability of stateful sets in Kubernetes
>>>
>>> -Akshit
>>>
>>

-- 

- John

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