start.yml

---
- name: Capture dstat version
  shell: "dstat --version | head -n 1"
  register: dstat_version

- name: Fail if dstat is not the correct version
  fail:
    msg: "Only Dstat 0.7.2 is allowed, you have {{ dstat_version }} installed"
  when: dstat_version.stdout != "Dstat 0.7.2"

- name: Remove previous /tmp/dstat.csv
  file:
    path: /tmp/dstat.csv
    state: absent

# This is necessary to clear disk caches, etc. This way the disk read
# and write statistics are consistent across test runs.
- name: Drop caches to reset state
  shell: echo 3 | sudo tee /proc/sys/vm/drop_caches

# We use dstat to periodically (every 1s) capture snapshots of system statistics.
# We output these snapshots to CSV for posterity.
#
# WARNING! - Do NOT change the options unless you are certain the CSV file is
#            backwards compatible. Changing the structure of this file makes it
#            very difficult to compare results across time with tools like Athena.
- name: Start dstat profiling
  command:
    argv: [
      "dstat",
      "--epoch",
      "--cpu",
      "--disk",
      "--io",
      "--load",
      "--mem",
      "--net",
      "--proc",
      "--proc-count",
      "--sys",
      "--socket",
      "--tcp",
      "--udp",
      "--vm",
      "--output", "/tmp/dstat.csv",
    ]
  async: 1000
  poll: 0
  register: dstat