From f5a750f19896f6f161876a5babc5b42c720dedf8 Mon Sep 17 00:00:00 2001 From: Yujun Zhang Date: Tue, 5 Sep 2017 20:11:42 +0800 Subject: Add host specific VM list to inspector design guide line JIRA: DOCTOR-73 Change-Id: I163b97ec87761538594034e926055646223af327 Signed-off-by: Yujun Zhang --- .../development/design/inspector-design-guideline.rst | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/development/design/inspector-design-guideline.rst b/docs/development/design/inspector-design-guideline.rst index 4add8c0f..faa5e424 100644 --- a/docs/development/design/inspector-design-guideline.rst +++ b/docs/development/design/inspector-design-guideline.rst @@ -31,7 +31,24 @@ Guidelines Host specific VMs list ---------------------- -TBD, see `DOCTOR-76`_. +While requirement in doctor project is to have alarm about fault to consumer in one second, it is just a limit we have +set in requirements. When talking about fault management in Telco, the implementation needs to be by all means optimal +and the one second is far from traditional Telco requirements. + +One thing to be optimized in inspector is to eliminate the need to read list of host specific VMs from Nova API, when +it gets a host specific failure event. Optimal way of implementation would be to initialize this list when Inspector +start by reading from Nova API and after this list would be kept up-to-date by ``instance.update`` notifications +received from nova. Polling Nova API can be used as a complementary channel to make snapshot of hosts and VMs list in +order to keep the data consistent with reality. + +This is enhancement and not perhaps something needed to keep under one second in a small system. Anyhow this would be +something needed in case of production use. + +This guideline can be summarized as following: + +- cache the host VMs mapping instead of reading it on request +- subscribe and handle update notifications to keep the list up to date +- make snapshot periodically to ensure data consistency Parallel execution ------------------ -- cgit 1.2.3-korg