scripts: Introduce tablet-mon.py

[tgrabiec]

It is a simple monitoring app which visualizes tablet metadata and changes of that metadata using animations. It allows one to quickly see and evaluate actions of the tablet load balancer.

It connects to the cluster via CQL and periodically scans relevant system tables.

Usage:

./scripts/tablet-mon.py

[scylladb-promoter]

CI state SUCCESS - https://jenkins.scylladb.com/job/scylla-master/job/scylla-ci/3850/

[tchaikov]

in Python 3, objects are so-called new-style object by default, no need to inherit from object anymore.

[tgrabiec]

Yes. I changed the shebang to python3 and dropped the inheritance.

[raphaelsc]

@tgrabiec Do you think it's a good idea to introduce a concept of record and play to the script? So this becomes a tool aid to debug production issues in the load balancer.

[scylladb-promoter]

CI state FAILURE - https://jenkins.scylladb.com/job/scylla-master/job/scylla-ci/3868/

[tchaikov]

@tgrabiec Do you think it's a good idea to introduce a concept of record and play to the script? So this becomes a tool aid to debug production issues in the load balancer.

that'd be fun at least =) so we just need to dump a time series of the query results of topo_query and tablets_query. what is missing is probably

1. dump these outputs to two tracing files
2. instead of reading from cluster, replay by reading from these files (one can even fast forward/backward =)

[tgrabiec]

ping @avikivity

[avikivity]

Please add copyright/license, plus some blurb that it's not a supported tool.

[nyh]

Very nice!
Makes me sad I don't know anything about pygame - I want to learn it too.

[tgrabiec]

In V3:

• Added license
• And short blurb about purpose and no warranty

[scylladb-promoter]

🟢 CI State: SUCCESS

✅ - Build
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✅ - Unit Tests

Build Details:

• Build URL: https://jenkins.scylladb.com/job/scylla-master/job/scylla-ci/4949/
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