.. _analyze: Performance *********** The :command:`analyze` subcommand helps to analyze ``cloud-init`` boot time performance. It is loosely based on ``systemd-analyze``, where there are four subcommands: - :command:`blame` - :command:`show` - :command:`dump` - :command:`boot` The analyze subcommand works by parsing the cloud-init log file for timestamps associated with specific events. Usage ===== The :command:`analyze` command requires one of the four subcommands: .. code-block:: shell-session $ cloud-init analyze blame $ cloud-init analyze show $ cloud-init analyze dump $ cloud-init analyze boot Availability ============ The :command:`analyze boot` subcommand only works on operating systems that use `systemd`. Subcommands =========== :command:`Blame` ---------------- The :command:`blame` subcommand matches :command:`systemd-analyze blame` where it prints, in descending order, the units that took the longest time to run. This output is highly useful for examining where ``cloud-init`` is spending its time. .. code-block:: shell-session $ cloud-init analyze blame Example output: .. code-block:: -- Boot Record 01 -- 00.80300s (init-network/config-growpart) 00.64300s (init-network/config-resizefs) 00.62100s (init-network/config-ssh) 00.57300s (modules-config/config-grub_dpkg) 00.40300s (init-local/search-NoCloud) 00.38200s (init-network/config-users_groups) 00.19800s (modules-config/config-apt_configure) 00.03700s (modules-final/config-keys_to_console) 00.02100s (init-network/config-update_etc_hosts) 00.02100s (init-network/check-cache) 00.00800s (modules-final/config-ssh_authkey_fingerprints) 00.00800s (init-network/consume-vendor-data) 00.00600s (modules-config/config-timezone) 00.00500s (modules-final/config-final_message) 00.00400s (init-network/consume-user-data) 00.00400s (init-network/config-mounts) 00.00400s (init-network/config-disk_setup) 00.00400s (init-network/config-bootcmd) 00.00400s (init-network/activate-datasource) 00.00300s (init-network/config-update_hostname) 00.00300s (init-network/config-set_hostname) 00.00200s (modules-final/config-snappy) 00.00200s (init-network/config-rsyslog) 00.00200s (init-network/config-ca_certs) 00.00200s (init-local/check-cache) 00.00100s (modules-final/config-scripts_vendor) 00.00100s (modules-final/config-scripts_per_once) 00.00100s (modules-final/config-salt_minion) 00.00100s (modules-final/config-phone_home) 00.00100s (modules-final/config-package_update_upgrade_install) 00.00100s (modules-final/config-fan) 00.00100s (modules-config/config-ubuntu_pro) 00.00100s (modules-config/config-ssh_import_id) 00.00100s (modules-config/config-snap) 00.00100s (modules-config/config-set_passwords) 00.00100s (modules-config/config-runcmd) 00.00100s (modules-config/config-locale) 00.00100s (modules-config/config-byobu) 00.00100s (modules-config/config-apt_pipelining) 00.00100s (init-network/config-write_files) 00.00100s (init-network/config-seed_random) 00.00000s (modules-final/config-ubuntu_drivers) 00.00000s (modules-final/config-scripts_user) 00.00000s (modules-final/config-scripts_per_instance) 00.00000s (modules-final/config-scripts_per_boot) 00.00000s (modules-final/config-puppet) 00.00000s (modules-final/config-power_state_change) 00.00000s (modules-final/config-mcollective) 00.00000s (modules-final/config-lxd) 00.00000s (modules-final/config-landscape) 00.00000s (modules-final/config-chef) 00.00000s (modules-config/config-snap_config) 00.00000s (modules-config/config-ntp) 00.00000s (modules-config/config-disable_ec2_metadata) 00.00000s (init-network/setup-datasource) 1 boot records analyzed :command:`Show` --------------- The :command:`show` subcommand is similar to :command:`systemd-analyze critical-chain` which prints a list of units, the time they started and how long they took. ``Cloud-init`` has five :ref:`boot stages`, and within each stage a number of modules may run depending on configuration. :command:`cloudinit-analyze show` will, for each boot, print this information and a summary of the total time. The following is an abbreviated example of the :command:`show` subcommand: .. code-block:: shell-session $ cloud-init analyze show Example output: .. code-block:: shell-session -- Boot Record 01 -- The total time elapsed since completing an event is printed after the "@" character. The time the event takes is printed after the "+" character. Starting stage: init-local |``->no cache found @00.01700s +00.00200s |`->found local data from DataSourceNoCloud @00.11000s +00.40300s Finished stage: (init-local) 00.94200 seconds Starting stage: init-network |`->restored from cache with run check: DataSourceNoCloud [seed=/dev/sr0][dsmode=net] @04.79500s +00.02100s |`->setting up datasource @04.88900s +00.00000s |`->reading and applying user-data @04.90100s +00.00400s |`->reading and applying vendor-data @04.90500s +00.00800s |`->activating datasource @04.95200s +00.00400s Finished stage: (init-network) 02.72100 seconds Starting stage: modules-config |`->config-snap ran successfully @15.43100s +00.00100s ... |`->config-runcmd ran successfully @16.22300s +00.00100s |`->config-byobu ran successfully @16.23400s +00.00100s Finished stage: (modules-config) 00.83500 seconds Starting stage: modules-final |`->config-snappy ran successfully @16.87400s +00.00200s |`->config-package_update_upgrade_install ran successfully @16.87600s +00.00100s ... |`->config-final_message ran successfully @16.93700s +00.00500s |`->config-power_state_change ran successfully @16.94300s +00.00000s Finished stage: (modules-final) 00.10300 seconds Total Time: 4.60100 seconds 1 boot records analyzed If additional boot records are detected then they are printed out from oldest to newest. :command:`Dump` --------------- The :command:`dump` subcommand simply dumps the ``cloud-init`` logs that the :command:`analyze` module is performing its analysis on, and returns a list of dictionaries that can be consumed for other reporting needs. Each element in the list is a boot entry. .. code-block:: shell-session $ cloud-init analyze dump Example output: .. code-block:: [ { "description": "starting search for local datasources", "event_type": "start", "name": "init-local", "origin": "cloudinit", "timestamp": 1567057578.037 }, { "description": "attempting to read from cache [check]", "event_type": "start", "name": "init-local/check-cache", "origin": "cloudinit", "timestamp": 1567057578.054 }, { "description": "no cache found", "event_type": "finish", "name": "init-local/check-cache", "origin": "cloudinit", "result": "SUCCESS", "timestamp": 1567057578.056 }, { "description": "searching for local data from DataSourceNoCloud", "event_type": "start", "name": "init-local/search-NoCloud", "origin": "cloudinit", "timestamp": 1567057578.147 }, { "description": "found local data from DataSourceNoCloud", "event_type": "finish", "name": "init-local/search-NoCloud", "origin": "cloudinit", "result": "SUCCESS", "timestamp": 1567057578.55 }, { "description": "searching for local datasources", "event_type": "finish", "name": "init-local", "origin": "cloudinit", "result": "SUCCESS", "timestamp": 1567057578.979 }, { "description": "searching for network datasources", "event_type": "start", "name": "init-network", "origin": "cloudinit", "timestamp": 1567057582.814 }, { "description": "attempting to read from cache [trust]", "event_type": "start", "name": "init-network/check-cache", "origin": "cloudinit", "timestamp": 1567057582.832 }, ... { "description": "config-power_state_change ran successfully", "event_type": "finish", "name": "modules-final/config-power_state_change", "origin": "cloudinit", "result": "SUCCESS", "timestamp": 1567057594.98 }, { "description": "running modules for final", "event_type": "finish", "name": "modules-final", "origin": "cloudinit", "result": "SUCCESS", "timestamp": 1567057594.982 } ] :command:`Boot` --------------- The :command:`boot` subcommand prints out kernel-related timestamps that are not included in any of the ``cloud-init`` logs. There are three different timestamps that are presented to the user: - ``kernel start`` - ``kernel finish boot`` - ``cloud-init start`` This was added for additional clarity into the boot process that ``cloud-init`` does not have control over, to aid in debugging performance issues related to ``cloud-init`` startup, and tracking regression. .. code-block:: shell-session $ cloud-init analyze boot Example output: .. code-block:: -- Most Recent Boot Record -- Kernel Started at: 2019-08-29 01:35:37.753790 Kernel ended boot at: 2019-08-29 01:35:38.807407 Kernel time to boot (seconds): 1.053617000579834 Cloud-init activated by systemd at: 2019-08-29 01:35:43.992460 Time between Kernel end boot and Cloud-init activation (seconds): 5.185053110122681 Cloud-init start: 2019-08-29 08:35:45.867000 successful Timestamp gathering ------------------- The following boot-related timestamps are gathered on demand when :command:`cloud-init analyze boot` runs: - Kernel startup gathered from system uptime - Kernel finishes initialization from systemd ``UserSpaceMonotonicTimestamp`` property - ``Cloud-init`` activation from the property ``InactiveExitTimestamp`` of the ``cloud-init`` local systemd unit In order to gather the necessary timestamps using systemd, running the following command will gather the ``UserspaceTimestamp``: .. code-block:: shell-session $ systemctl show -p UserspaceTimestampMonotonic Example output: .. code-block:: UserspaceTimestampMonotonic=989279 The ``UserspaceTimestamp`` tracks when the init system starts, which is used as an indicator of the kernel finishing initialisation. Running the following command will gather the ``InactiveExitTimestamp``: .. code-block:: shell-session $ systemctl show cloud-init-local -p InactiveExitTimestampMonotonic Example output: .. code-block:: InactiveExitTimestampMonotonic=4493126 The ``InactiveExitTimestamp`` tracks when a particular systemd unit transitions from the `Inactive` to `Active` state, which can be used to mark the beginning of systemd's activation of ``cloud-init``. Currently this only works for distros that use systemd as the init process. We will be expanding support for other distros in the future and this document will be updated accordingly. If systemd is not present on the system, ``dmesg`` is used to attempt to find an event that logs the beginning of the init system. However, with this method only the first two timestamps are able to be found; ``dmesg`` does not monitor userspace processes, so no ``cloud-init`` start timestamps are emitted -- unlike when using systemd.