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(Updated July 7, 2017, 11:52 p.m.) Review request for Aurora, David McLaughlin, Mehrdad Nurolahzade, Santhosh Kumar Shanmugham, and Zameer Manji. Changes ------- Make the 'watch' step of aurora job restart retryable. Bugs: AURORA-1940 https://issues.apache.org/jira/browse/AURORA-1940 Repository: aurora Description (updated) ------- aurora job restart request should be idempotent and retryable. There was a recent change to the Aurora client to provide "at most once" instead of "at least once" retries for non-idempotent operations. See: https://github.com/apache/aurora/commit/f1e25375def5a047da97d8bdfb47a3a9101568f6 Technically, `aurora job restart` is a non-idempotent operation, thus it was not retried. However, when a transport exception occurs, the operator has to babysit simple operations like aurora job restart if it were not retried. Compared to the requests that were causing problems (admin tasks, job creating, updates, etc.), restarts in general should be retried rather than erring on the side of caution. Job restart can be divided into three steps: - 1. get instance status (getTasksWithoutConfigs) - 2. restart shards (restartShards) - 3. watch instance until healthy (getTasksWithoutConfigs) TTransport exception can be thrown at each of these step, ideally we should make __ALL__ of the steps above __idempotent__ and retryable. The only trickey part is that the `watch` logic is also used in --wait-until options of job create/add command, making this step retryable will have an impact on job create/add commands as well. In this CR, I will make the first __TWO__ steps retryable since they are self-contained in job restart command. If people are OK with this strategy, I'll make the `watch` step retryable as well. __Updates__: I made the `watch` step in `aurora job restart` retryable in the 3rd revision. Note the `InstanceWatcher` in `Restarter` relies on `StatusHelper.get_tasks` method to query the latest instance status. This method is also invoked by JobMonitor during job create/add. The solution here is to pass a `retry` flag to this method, so that it can be customized for different scenarios. __Open Question__: Currently, `aurora job create --wait-until RUNNING` fails immediately if there is any transport exception during the `wait` step. Do we need retry for the `wait` step? Diffs (updated) ----- src/main/python/apache/aurora/client/api/instance_watcher.py a35fb22edc9a5bb12f286856b170f5cb0170eceb src/main/python/apache/aurora/client/api/restarter.py 6600c6b608ee70a02e11ca8550a06b7fb76fd863 src/main/python/apache/aurora/client/api/task_util.py fb7c76f42171737701c740fddf893f07211a47a0 src/test/python/apache/aurora/api_util.py bd6e3a6abb5a2eec621121fc1b4d547c54a9d19d src/test/python/apache/aurora/client/api/test_instance_watcher.py 8fd419f812c6e038e6f7fba0a662da0a6410b794 src/test/python/apache/aurora/client/api/test_job_monitor.py 537abd38cd13bcbb615c0224c983868b29027379 src/test/python/apache/aurora/client/api/test_restarter.py a81003e79e090bbfa151431366f5394f405d99eb src/test/python/apache/aurora/client/api/test_task_util.py 365ef59857003402c4354e06abeaea947d49322b src/test/python/apache/aurora/client/cli/test_command_hooks.py a44a25fb1e4357780adca4403b6010d160066b21 src/test/python/apache/aurora/client/cli/test_create.py 3b09bb25e919bac2795ccd56bd98657b1f98690b src/test/python/apache/aurora/client/cli/test_plugins.py 762735e00bd8051ab64674e7ee359758d3cbeca7 src/test/python/apache/aurora/client/cli/test_restart.py cb4adc55caec354d2cdf6a92ff2dd8a3b4a9eca8 Diff: https://reviews.apache.org/r/60714/diff/3/ Changes: https://reviews.apache.org/r/60714/diff/2-3/ Testing (updated) ------- ./build-support/jenkins/build.sh To test the retry logic, TTranport exceptions were randomly thrown at the client side(for all api calls to the scheduler proxy, there is a 50% chance of throwing TTranport exception), aurora job restart command was issued against scheduler, and the output was like: ``` vagrant@aurora:~$ aurora job restart devcluster/vagrant/test/hello WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... INFO] Performing rolling restart of job devcluster/vagrant/test/hello (instances: [0]) INFO] Restarting instances: [0] WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... INFO] Watching instances: [0] WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... INFO] Detected RUNNING instance 0 WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... WARN] Transport error communicating with scheduler: Timed out talking to http://aurora.local:8081/api, retrying... INFO] Instance 0 has been up and healthy for at least 30 seconds INFO] All instances were restarted successfully Job devcluster/vagrant/test/hello restarted successfully ``` Thanks, Kai Huang