<p>I have successfully installed dse in my kubernetes environment using the Kubernetes Operator instructions:</p>

<p>With nodetool I checked that all pod successfully joined the ring</p>

<p>The problem is that when I reboot one of the kubernetes node the cassandra pod that was running on that node never recover:</p>

<pre><code>[root@node1 ~]# kubectl exec -it -n cassandra cluster1-dc1-r2-sts-0 -c cassandra nodetool status
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving/Stopped
-- Address Load Tokens Owns (effective) Host ID Rack
UN 10.244.166.132 153.82 KiB 1 77.9% 053cc18e-397c-4abe-bb1b-d48a3fef3c93 r3
DS 10.244.104.1 136.09 KiB 1 26.9% 8ae31e1c-856e-44a8-b081-c5c040b535b9 r1
UN 10.244.135.2 202.8 KiB 1 95.2% 06200794-298c-4122-b8ff-4239bc7a8ded r2

[root@node1 ~]# kubectl get pods -n cassandra
NAME READY STATUS RESTARTS AGE
cass-operator-56f5f8c7c-w6l2c 1/1 Running 0 17h
cluster1-dc1-r1-sts-0 1/2 Running 2 17h
cluster1-dc1-r2-sts-0 2/2 Running 0 17h
cluster1-dc1-r3-sts-0 2/2 Running 0 17h
</code></pre>

<p>I have looked into the logs but I can't figure out what is the problem.</p>

<p>The "kubectl logs"" command return the logs below:</p>

<pre><code>INFO  [nioEventLoopGroup-2-1] 2020-03-25 12:13:13,536 Cli.java:555 - address=/192.168.0.11:38590 url=/api/v0/probes/liveness status=200 OK
INFO  [epollEventLoopGroup-6506-1] 2020-03-25 12:13:14,110 Clock.java:35 - Could not access native clock (see debug logs for details), falling back to Java system clock
WARN  [epollEventLoopGroup-6506-2] 2020-03-25 12:13:14,111 Slf4JLogger.java:146 - Unknown channel option 'TCP_NODELAY' for channel '[id: 0x8a898bf3]'
WARN  [epollEventLoopGroup-6506-2] 2020-03-25 12:13:14,116 Loggers.java:28 - [s6501] Error connecting to /tmp/dse.sock, trying next node
java.io.FileNotFoundException: null
        at io.netty.channel.unix.Errors.throwConnectException(Errors.java:110)
        at io.netty.channel.unix.Socket.connect(Socket.java:257)
        at io.netty.channel.epoll.AbstractEpollChannel.doConnect0(AbstractEpollChannel.java:732)
        at io.netty.channel.epoll.AbstractEpollChannel.doConnect(AbstractEpollChannel.java:717)
        at io.netty.channel.epoll.EpollDomainSocketChannel.doConnect(EpollDomainSocketChannel.java:87)
        at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.connect(AbstractEpollChannel.java:559)
        at io.netty.channel.DefaultChannelPipeline$HeadContext.connect(DefaultChannelPipeline.java:1366)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:545)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:530)
        at io.netty.channel.ChannelOutboundHandlerAdapter.connect(ChannelOutboundHandlerAdapter.java:47)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:545)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:530)
        at io.netty.channel.ChannelDuplexHandler.connect(ChannelDuplexHandler.java:50)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:545)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:530)
        at io.netty.channel.ChannelDuplexHandler.connect(ChannelDuplexHandler.java:50)
        at com.datastax.oss.driver.internal.core.channel.ConnectInitHandler.connect(ConnectInitHandler.java:57)
        at io.netty.channel.AbstractChannelHandlerContext.invokeConnect(AbstractChannelHandlerContext.java:545)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:530)
        at io.netty.channel.AbstractChannelHandlerContext.connect(AbstractChannelHandlerContext.java:512)
        at io.netty.channel.DefaultChannelPipeline.connect(DefaultChannelPipeline.java:1024)
        at io.netty.channel.AbstractChannel.connect(AbstractChannel.java:276)
        at io.netty.bootstrap.Bootstrap$3.run(Bootstrap.java:252)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:375)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Thread.java:748)
INFO  [nioEventLoopGroup-2-2] 2020-03-25 12:13:14,118 Cli.java:555 - address=/192.168.0.11:38592 url=/api/v0/probes/readiness status=500 Internal Server Error
</code></pre>

<p>The error <code>java.io.FileNotFoundException: null</code> appears also when cassandra starts successfully.</p>

<p>So what remains is the error:</p>

<pre><code>address=/192.168.0.11:38592 url=/api/v0/probes/readiness status=500 Internal Server Error
</code></pre>

<p>Which doesn't say much to me.</p>

<p>The "kubectl describe" shows the following</p>

<pre><code>Warning Unhealthy 4m41s (x6535 over 18h) kubelet, node2 Readiness probe failed: HTTP probe failed with statuscode: 500
</code></pre>

<p>In the cassandra container only this process is running:</p>

<pre><code>java -Xms128m -Xmx128m -jar /opt/dse/resources/management-api/management-api-6.8.0.20200316-LABS-all.jar --dse-socket /tmp/dse.sock --host tcp://0.0.0.0```
</code></pre>

<p>And in the <code>/var/log/cassandra/system.log</code> I can't point out any error</p>

Andrea
<p>Andrea, the error "java.io.FileNotFoundException: null" is a harmless message about a transient error during the Cassandra pod starting up and healthcheck.</p>

<p>I was able to reproduce the issue you ran into. If you run <code>kubectl get pods</code> you should see the affected pod showing 1/2 under "READY" column, this means the Cassandra container was not brought up in the auto-restarted pod. Only the management API container is running. I suspect this is a bug in the operator and I'll work with the developers to sort it out.</p>

<p>As a workaround you can run <code>kubectl delete pod/&lt;pod_name&gt;</code> to recover your Cassandra cluster back to a normal state (in your case <code>kubectl delete pod/cluster1-dc1-r1-sts-0</code>). This will redeploy the pod and remount the data volume automatically, without losing anything.</p>
