Performance analysis

Occasionally, instances don’t perform as well as expected, and so we provide a simple tool to inspect which operations took the longest during boot and setup.

cloud-init analyze

The cloud-init command has an analysis sub-command, analyze, which parses any cloud-init.log file into formatted and sorted events. This analysis reveals the most costly cloud-init operations and which configuration options are responsible. These subcommands default to reading /var/log/cloud-init.log.

analyze show

Parse and organise cloud-init.log events by stage and include each sub-stage granularity with time delta reports.

$ cloud-init analyze show -i my-cloud-init.log

Example output:

-- Boot Record 01 --
The total time elapsed since completing an event is printed after the "@"
The time the event takes is printed after the "+" character.

Starting stage: modules-config
|`->config-snap_config ran successfully @05.47700s +00.00100s
|`->config-ssh-import-id ran successfully @05.47800s +00.00200s
|`->config-locale ran successfully @05.48000s +00.00100s

analyze dump

Parse cloud-init.log into event records and return a list of dictionaries that can be consumed for other reporting needs.

$ cloud-init analyze dump -i my-cloud-init.log

Example output:

  "description": "running config modules",
  "event_type": "start",
  "name": "modules-config",
  "origin": "cloudinit",
  "timestamp": 1510807493.0

analyze blame

Parse cloud-init.log into event records and sort them based on the highest time cost for a quick assessment of areas of cloud-init that may need improvement.

$ cloud-init analyze blame -i my-cloud-init.log

Example output:

-- Boot Record 11 --
     00.01300s (modules-final/config-scripts-per-boot)
     00.00400s (modules-final/config-final-message)

analyze boot

Make subprocess calls to the kernel in order to get relevant pre-cloud-init timestamps, such as the kernel start, kernel finish boot, and cloud-init start.

$ cloud-init analyze boot

Example output:

-- Most Recent Boot Record --
    Kernel Started at: 2019-06-13 15:59:55.809385
    Kernel ended boot at: 2019-06-13 16:00:00.944740
    Kernel time to boot (seconds): 5.135355
    Cloud-init start: 2019-06-13 16:00:05.738396
    Time between Kernel boot and Cloud-init start (seconds): 4.793656