monitord

monitord ... know how happy your systemd is! 😊

We offer the following run modes:

• systemd-timer (legacy cron would work too)
  • Refer to monitord.timer and monitord.service unit files
  • Ensure no daemon: mode options are set in monitord.conf
• daemon mode
  • Enable daemon mode in configuration file
  • Stats will be written to stdout every daemon_stats_refresh_secs

Open to more formats / run methods ... Open an issue to discuss. Depends on the dependencies basically.

monitord is a config driven binary. We plan to keep CLI arguments to a minimum.

INFO level logging is enabled to stderr by default. Use -l LEVEL to increase or decrease logging.

Install

Install via cargo or use as a dependency in your Cargo.toml.

• cargo install monitord
• Create (copy from repo) a monitord.conf
  • Defaults to looking for it at /etc/monitord.conf
• monitord --help

crl-linux:monitord cooper$ monitord --help
monitord: Know how happy your systemd is! 😊

Usage: monitord [OPTIONS]

Options:
  -c, --config <CONFIG>
          Location of your monitord config

          [default: /etc/monitord.conf]

  -l, --log-level <LOG_LEVEL>
          Adjust the console log-level

          [default: Info]
          [possible values: error, warn, info, debug, trace]

  -h, --help
          Print help (see a summary with '-h')

  -V, --version
          Print version

Config

monitord can have the different components monitored. To enable / disabled set the following in our monitord.conf. This file is ini format to match systemd unit files.

# Pure ini - no yes/no for bools

[monitord]
# Set a custom dbus address to connect to
# OPTIONAL: If not set, we default to the Unix socket below
dbus_address = unix:path=/run/dbus/system_bus_socket
# Timeout in seconds for dbus connection/collections
# OPTIONAL: default is 30 seconds
dbus_timeout = 30
# Run as a daemon or 1 time
daemon = false
# Time to refresh systemd stats in seconds
# Daemon mode only
daemon_stats_refresh_secs = 60
# Prefix flat-json key with this value
# The value automatically gets a '.' appended (so don't put here)
key_prefix = monitord
# cron/systemd timer output format
# Supported: json, json-flat, json-pretty
output_format = json

# Grab networkd stats from files + networkctl
[networkd]
enabled = true
link_state_dir = /run/systemd/netif/links

# Enable grabbing PID 1 stats via procfs
[pid1]
enabled = true

# Services to grab extra stats for
# .service is important as that's what DBus returns from `list_units`
[services]
foo.service

[timers]
enabled = true

[timers.allowlist]
foo.timer

[timers.blocklist]
bar.timer

# Grab unit status counts via dbus
[units]
enabled = true
state_stats = true

# Filter what services you want collect state stats for
# If both lists are configured blocklist is preferred
# If neither exist all units state will generate counters
[units.state_stats.allowlist]
foo.service

[units.state_stats.blocklist]
bar.service

# machines config
[machines]
enabled = true

# Same rules apply as state_stats lists above
[machines.allowlist]
foo

[machines.blocklist]
bar

Machines support

From version >=0.11 monitord supports obtaining the same set of key from systemd 'machines' (i.e. machinectl --list).

The keys are the same format as below in json_flat output but are prefixed with the machine keyword and machine name. For example:

# $KEY_PREFIX.machine.$MACHINE_NAME
{
  ...
  "monitord.machine.foo.pid1.fd_count": 69,
  ...
}

Output Formats

json

Normal serde_json non pretty JSON. All on one line. Most compact format.

json-flat

Move all key value pairs to the top level and . notate compononets + sub values. Is semi pretty too + custom. All unittested ...

{
  "networkd.eno4.address_state": 3,
  "networkd.eno4.admin_state": 4,
  "networkd.eno4.carrier_state": 5,
  "networkd.eno4.ipv4_address_state": 3,
  "networkd.eno4.ipv6_address_state": 2,
  "networkd.eno4.oper_state": 9,
  "networkd.eno4.required_for_online": 1,
  "networkd.managed_interfaces": 2,
  "networkd.wg0.address_state": 3,
  "networkd.wg0.admin_state": 4,
  "networkd.wg0.carrier_state": 5,
  "networkd.wg0.ipv4_address_state": 3,
  "networkd.wg0.ipv6_address_state": 3,
  "networkd.wg0.oper_state": 9,
  "networkd.wg0.required_for_online": 1,
  "pid1.cpu_time_kernel": 48,
  "pid1.cpu_user_kernel": 41,
  "pid1.fd_count": 245,
  "pid1.memory_usage_bytes": 19165184,
  "pid1.tasks": 1,
  "services.chronyd.service.active_enter_timestamp": 1683556542382710,
  "services.chronyd.service.active_exit_timestamp": 0,
  "services.chronyd.service.cpuusage_nsec": 328951000,
  "services.chronyd.service.inactive_exit_timestamp": 1683556541360626,
  "services.chronyd.service.ioread_bytes": 18446744073709551615,
  "services.chronyd.service.ioread_operations": 18446744073709551615,
  "services.chronyd.service.memory_available": 18446744073709551615,
  "services.chronyd.service.memory_current": 5214208,
  "services.chronyd.service.nrestarts": 0,
  "services.chronyd.service.restart_usec": 100000,
  "services.chronyd.service.state_change_timestamp": 1683556542382710,
  "services.chronyd.service.status_errno": 0,
  "services.chronyd.service.tasks_current": 1,
  "services.chronyd.service.timeout_clean_usec": 18446744073709551615,
  "services.chronyd.service.watchdog_usec": 0,
  "system-state": 3,
  "timers.fstrim.timer.accuracy_usec": 3600000000,
  "timers.fstrim.timer.fixed_random_delay": 0,
  "timers.fstrim.timer.last_trigger_usec": 1743397269608978,
  "timers.fstrim.timer.last_trigger_usec_monotonic": 0,
  "timers.fstrim.timer.next_elapse_usec_monotonic": 0,
  "timers.fstrim.timer.next_elapse_usec_realtime": 1744007133996149,
  "timers.fstrim.timer.persistent": 1,
  "timers.fstrim.timer.randomized_delay_usec": 6000000000,
  "timers.fstrim.timer.remain_after_elapse": 1,
  "timers.fstrim.timer.service_unit_last_state_change_usec": 1743517244700135,
  "timers.fstrim.timer.service_unit_last_state_change_usec_monotonic": 639312703,
  "unit_states.chronyd.service.active_state": 1,
  "unit_states.chronyd.service.loaded_state": 1,
  "unit_states.chronyd.service.unhealthy": 0,
  "units.active_units": 403,
  "units.automount_units": 1,
  "units.device_units": 150,
  "units.failed_units": 0,
  "units.inactive_units": 159,
  "units.jobs_queued": 0,
  "units.loaded_units": 497,
  "units.masked_units": 25,
  "units.mount_units": 52,
  "units.not_found_units": 38,
  "units.path_units": 4,
  "units.scope_units": 17,
  "units.service_units": 199,
  "units.slice_units": 7,
  "units.socket_units": 28,
  "units.target_units": 54,
  "units.timer_units": 20,
  "units.total_units": 562,
  "version": "255.7-1.fc40"
}

json-pretty

Normal serde_json pretty representations of each components structs.

Development

To do test runs (requires systemd and systemd-networkd installed)

• Pending what you have enabled in your config ...

• cargo run -- -c monitord.conf -l debug

Ensure the following pass before submitting a PR (CI checks):

• cargo test
• cargo clippy
• cargo fmt

Generate codegen APIs

• cargo install zbus_xmlgen
• zbus-xmlgen system org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/chronyd_2eservice

Then add the following macros to tell clippy to go away:

#![allow(warnings)]
#![allow(clippy)]

Non Linux development

Sometimes I develop from my Mac OS X laptop. So I thought I'd document and add the way I build a Fedora Rawhide container and mount the local repo to /repo in the container to run monitord and test.

• Build the image (w/git, rust tools and systemd)
  • docker build -t monitord-dev .
• Start via systemd and mount the monitord repo to /repo
  • docker run --rm --name monitord-dev -it --privileged --tmpfs /run --tmpfs /tmp -v $(pwd):/repo monitord-dev /sbin/init
    • --rm is optional but will remove the container when stopped

You can now log into the container to build + run tests and run the binary now against systemd.

• docker exec -it monitord-dev bash
• cd /repo ; cargo run -- -c monitord
  • networkd etc. are not running my default but can be started ...
  • systemctl start systemd-networkd
    • No interfaces will be managed tho by default in the container ...

API Usage

DBus

All monitord's dbus is done via async (tokio) zbus crate.

systemd Dbus APIs are in use in the following modules:

• machines
  • ManagerProxy::list_machines()
  • Can do most other calls then on the machine's systemd/dbus
• networkd
  • ManagerProxy::list_links()
  • Would love to stop parsing /run/systemd/netif/links and replace via varlink API
    • https://github.com/systemd/systemd/issues/36877
• system
  • ManagerProxy::get_version()
  • ManagerProxy::system_state()
• timer
  • TimerProxy::unit() - Find service unit of timer
  • ManagerProxy::get_unit()
  • UnitProxy::state_change_timestamp()
  • UnitProxy::state_change_timestamp_monotonic()
• units
  • ManagerProxy::list_units() - Main counting of unit stats
  • ServiceProxy::cpuusage_nsec()
  • ServiceProxy::ioread_bytes()
  • ServiceProxy::ioread_operations()
  • ServiceProxy::memory_current()
  • ServiceProxy::memory_available()
  • ServiceProxy::nrestarts()
  • ServiceProxy::get_processes()
  • ServiceProxy::restart_usec()
  • ServiceProxy::status_errno()
  • ServiceProxy::tasks_current()
  • ServiceProxy::timeout_clean_usec()
  • ServiceProxy::watchdog_usec()
  • UnitProxy::active_enter_timestamp
  • UnitProxy::active_exit_timestamp
  • UnitProxy::inactive_exit_timestamp()
  • UnitProxy::state_change_timestamp() - Used for raw stat + time_in_state

Some of these modules can be disabled via configuration. Due to this, monitord might not always be running / calling all these DBus calls per run.

Varlink

None yet :(.

varlink 101

varlink might one day replace our DBUS usage. Here are some notes on how to work with systemd varlink as there isn't really documentation outside man pages.

Checking interfaces

• varlinkctl is your friend - https://man7.org/linux/man-pages/man1/varlinkctl.1.html

Here is an example with networkd's interfaces:

varlinkctl info unix:/run/systemd/netif/io.systemd.Network
varlinkctl introspect unix:/run/systemd/netif/io.systemd.Network io.systemd.Network

cooper@au:~$ varlinkctl call unix:/run/systemd/netif/io.systemd.Network io.systemd.Network.GetStates '{}' -j | jq
{
  "AddressState": "routable",
  "IPv4AddressState": "routable",
  "IPv6AddressState": "routable",
  "CarrierState": "carrier",
  "OnlineState": "online",
  "OperationalState": "routable"
}