Use docker to build cassandra jar file

[aledbf]

Test image: aledbf/cassandra:v15

This PR also replaces the java code with a go shared library.

fixes #190
fixes #147

[ahmetb]

It'd be great if you can find someone else who knows cassandra a little bit better than I do to review this, perhaps someone from sig-storage can help.

[ahmetb]

If this is good to go, do you mind finding a reviewer (perhaps the original developers of Cassandra example, or we can mention [@]kubernetes/sig-storage-pr-reviews).

[ahmetb]

Sorry I was late to review this. I don't understand the domain much but the code looks good + you're the owner for this example now.
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahmetb, aledbf

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[ahmetb]

@aledbf Let me know if the image needs re-pushing.

[aledbf]

@ahmetb yes, you need to publish the image.

[ahmetb]

@aledbf this fails to build:

/build.sh: line 33: CASSANDRA_VERSION: unbound variable
The command '/bin/sh -c clean-install bash     && /build.sh     && rm /build.sh' returned a non-zero code: 1
ERROR
ERROR: build step 0 "gcr.io/cloud-builders/docker" failed: exit status 1

[ahmetb]

My bad I probably should've used the makefile to build/push.

[ahmetb]

I pushed gcr.io/google-samples/cassandra:v14 (+-dev) please try out and update the documentation.

[wallrj]

This PR also replaces the java code with a go shared library.

Hi @aledbf. What was the motivation for introducing the Go shared library?

We were using the pure Java Kubernetes seed provider, but the addition of a Go shared library makes it more difficult for us to re-use this in Navigator.
See: jetstack/navigator#332 and jetstack/navigator#336

Not complaining, just grumbling 😉

[aledbf]

but the addition of a Go shared library makes it more difficult for us to re-use this in Navigator.

Why?

Hi @aledbf. What was the motivation for introducing the Go shared library?

Because doing this in go is cleaner than the previous code and also we can use client-go

[wallrj]

but the addition of a Go shared library makes it more difficult for us to re-use this in Navigator.

Why?

We're trying to use the Kubernetes Seed provider with the Cassandra images hosted on Dockerhub, not the images built for this demo.
So before, we had only to download the Jar artefact from the repository and add it to the Pod from an init container.
Now we also have to compile and install the Go shared object.

Hi @aledbf. What was the motivation for introducing the Go shared library?

Because doing this in go is cleaner than the previous code and also we can use client-go

Ok. Thanks for clarifying.

But note @chrislovecnm 's original plan was that this seed provider code might eventually be moved into the Cassandra code base:

Once stable these components are stable recommended that this code gets moved into the Apache Cassandra code base.
-- kubernetes/kubernetes#24286

With that in mind, I'd have thought it more likely to be accepted as a pure java implementation, perhaps using the official Java client for Kubernetes: https://github.com/kubernetes-client/java

Have you any plans to move the Kubernetes Seed Provider to a dedicated repository?
It is useful outside of this example.

[madireddyr]

@aledbf : when we tried gcr.io/google-samples/cassandra:v14 & 13 : we got below error
INFO 19:45:59 Unable to load cassandra-topology.properties; compatibility mode disabled
Exception (org.apache.cassandra.exceptions.ConfigurationException) encountered during startup: io.k8s.cassandra.KubernetesSeedProvider
Fatal configuration error; unable to start server. See log for stacktrace.
org.apache.cassandra.exceptions.ConfigurationException: io.k8s.cassandra.KubernetesSeedProvider
Fatal configuration error; unable to start server. See log for stacktrace.
at org.apache.cassandra.config.DatabaseDescriptor.applySeedProvider(DatabaseDescriptor.java:895)
at org.apache.cassandra.config.DatabaseDescriptor.applyAll(DatabaseDescriptor.java:324)
at org.apache.cassandra.config.DatabaseDescriptor.daemonInitialization(DatabaseDescriptor.java:142)
at org.apache.cassandra.service.CassandraDaemon.applyConfig(CassandraDaemon.java:647)
at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:582)
at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:691)
ERROR 19:45:59 Exception encountered during startup
org.apache.cassandra.exceptions.ConfigurationException: io.k8s.cassandra.KubernetesSeedProvider
Fatal configuration error; unable to start server. See log for stacktrace.
at org.apache.cassandra.config.DatabaseDescriptor.applySeedProvider(DatabaseDescriptor.java:895) ~[apache-cassandra-3.11.2.jar:3.11.2]
at org.apache.cassandra.config.DatabaseDescriptor.applyAll(DatabaseDescriptor.java:324) ~[apache-cassandra-3.11.2.jar:3.11.2]
at org.apache.cassandra.config.DatabaseDescriptor.daemonInitialization(DatabaseDescriptor.java:142) ~[apache-cassandra-3.11.2.jar:3.11.2]
at org.apache.cassandra.service.CassandraDaemon.applyConfig(CassandraDaemon.java:647) [apache-cassandra-3.11.2.jar:3.11.2]
at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:582) [apache-cassandra-3.11.2.jar:3.11.2]
at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:691) [apache-cassandra-3.11.2.jar:3.11.2]

i tried above example with aledbf/cassandra:v15 and it worked . not sure whats the difference between
gcr.io/google-samples/cassandra:v14 & aledbf/cassandra:v15

i see aledbf/cassandra:v15 got merged could you point me committed image(seems aledbf/cassandra:v15 is a test image)

[mkobit]

@madireddyr It doesn't look like the gcr.io/google-samples/cassandra:v14 tag was updated with these changes