Kevin W Monroe created BIGTOP-2836: -------------------------------------- Summary: charm metric collector race condition Key: BIGTOP-2836 URL: https://issues.apache.org/jira/browse/BIGTOP-2836 Project: Bigtop Issue Type: Bug Components: deployment Affects Versions: 1.2.0, 1.2.1 Reporter: Kevin W Monroe Assignee: Kevin W Monroe Priority: Minor Fix For: 1.3.0
Initially thought fixed in BIGTOP-2801, it seems the charm metric collector can still cause a failed deployment. As a refresher, metrics give users the ability see stuff like how many datanodes or zookeeper peers are deployed in an environment. The first attempt at fixing this was to include a precondition before collecting metrics, for example, ensure the namenode is "ready" before running "hdfs getconf". However, in this example, there can be a period of time where the charm tells the NN to start (at which point the "ready" state is set), yet the NN takes a while to format HDFS. If the metric collector runs during this time, 'hdfs getconf' will fail, which means the metric hook fails, which means the deployment fails. There are a variety of ways to mitigate this: 1. Don't set "ready" until the NN is all the way up. 2. Don't let a metric hook fail the entire deployment. 3. Alter the collector so it handles a failed 'hdfs getconf' gracefully. #1: added to our todo, but will take more time to implement. #2: opened an issue against the metric layer to see if this is possible. This JIRA will focus on fixing the problem with option #3. -- This message was sent by Atlassian JIRA (v6.4.14#64029)