5f1b76a0c7
Add the descriptions for All-In-One scenario and multiple nodes' scenario. Change-Id: I0849cb4655f989a23ba71d7312f8b85f35396780 Implements: blueprint update-readme
60 lines
2.2 KiB
ReStructuredText
60 lines
2.2 KiB
ReStructuredText
Scalpels
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========
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Scalpels is a distributed tracing or debuging system for OpenStack.
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Background
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==========
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OpenStack is made of multiple Python-based projects. Each project has similiar but different architecture. Scalpels intergates some useful scripts or 3rd tools to help operator track system status in your cloud environments.
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Contribute
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==========
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This project is a prototype now and is under development. If you have interests in this work, please contact @kun_huang, at #openstack-chinese channel.
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Mission
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=======
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Scalpels is a kind of "debugfs" for OpenStack. It gathers data from number of tracers like proc or systemtap which could be used to quantize preformance under workloads.
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Single Node Architecture
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========================
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This type of deployment is used as POC in OpenStack community CI.
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.. image:: doc/source/images/allinone.png
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:alt: All-in-One deployment
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In All-In-One scenario, Scalpels Client works as rpc client, Scalpels Agent works as rpc server. When Scalpels Agent receives a rpc to start tracer 3, it will start a unix process for tracer 3, which can write data to database. Scalpels Client can read data from database directly.
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Multiple Node Architecture
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==========================
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This is under Designing:
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.. image:: doc/source/images/multiple.png
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:alt: Multiple deployment
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In multiple nodes scenario, Scalpels Server are non-state servers, they are distributed in multiple nodes, each Scalpels Server knows all agents' location and could forward the request to start tracers.
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Scalpels Agent is introduced to manage trace process, it can be combined with Scalpels server during implementation.
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Tracers can write data into redis bus instead of database to keep data consistency.
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Agent-Tracer-Worker
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===================
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The relationship is:
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.. image:: doc/source/images/agent-tracer-worker.png
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:alt: agent-tracer-worker.png
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Scalpels Agent: manager tracers by start/stop signals.
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Tracer: Start worker process and write its stdout to database.
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Worker: It fetches data from operating system.
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Ideas
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=====
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Each project will have scripts working:
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* on python calls
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* on sql queries
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* on filesystem I/O
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* on RPC calls if need
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* on necessary system calls
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* on common system statistics
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