Jail Exporter is a Prometheus exporter for FreeBSD jail metrics as reported
by rctl(8).
The exporter is written in Rust and uses the jail and rctl crates to discover jails and obtain metrics.
jail_exporter is available in the FreeBSD ports tree as
sysutils/jail_exporter. It can be installed by either the binary package with
pkg install jail_exporter, or by compiling the package yourself in the ports
tree.
The crate is also available via crates.io, and can be installed using the
cargo install command. However, it is heavily recommended to install the
exporter via pkg(8) or the ports tree.
$ cargo install jail_exporterWhen installing via this method, you may want to move the installed binary to
/usr/local/sbin and obtain an appropriate rc(8) to start the exporter on
system boot. You can do this as follows:
# Performed as root.
$ mv ~/.cargo/bin/jail_exporter /usr/local/sbin/
$ chown root:wheel /usr/local/sbin/jail_exporter
$ jail_exporter --rc-script | tee /usr/local/etc/rc.d/jail_exporter
$ chmod 755 /usr/local/etc/rc.d/jail_exporterYou can enable jail_exporter to start at system boot via rc.conf(5).
# Either edit /etc/rc.conf directly or use the following command
sysrc jail_exporter_enable=YESAt a minimum, building Jail Exporter should require:
- Rust v1.74.1 (MSRV)
- Cargo
A BSD make(1) Makefile is provided for convenience, if you already have
Rust and Cargo available, executing make will build a debug release of Jail
Exporter at target/debug/jail_exporter. make release will build a release
version at target/release/jail_exporter.
If you don't wish to use make(1), the usual cargo build command should work
just fine.
Configuration can be performed either via command line arguments or environment variables. If both an environment variable and a command line argument are provided for the same option, the configuration will be taken from the command line argument.
| Argument | Default | Purpose |
|---|---|---|
--output.file-path |
N/A | Output metrics to a file instead of running an HTTPd. |
--rc-script |
N/A | Output an appropriate rc.d script |
--web.auth-config |
N/A | HTTP Basic authentication configuration file. |
--web.listen-address |
127.0.0.1:9452 |
Address on which to expose metrics and web interface. |
--web.telemetry-path |
/metrics |
Path under which to expose metrics. |
| Variable | Equivalent Argument |
|---|---|
OUTPUT_FILE_PATH |
output.file-path |
WEB_AUTH_CONFIG |
web.auth-config |
WEB_LISTEN_ADDRESS |
web.listen-address |
WEB_TELEMETRY_PATH |
web.telemetry-path |
HTTP Basic Authentication is available when the crate is compiled with the
auth feature. This feature is enabled by default.
The configuration file format is the same as specified in exporter-toolkit.
---
basic_auth_users:
username: 'bcrypt hashed secret'
another_user: 'bcrypt hashed secret'If no configuration is specified, or the configuration is specified but contains no users, authentication will be disabled.
While loading the configuration, usernames will be checked for compliance with
RFC7617. If any invalid usernames are detected, jail_exporter will error
out and refuse to start.
User passwords are bcrypt hashed secrets, which can be generated with the
bcrypt subcommand if jail_exporter was compiled with the bcrypt_cmd
feature (enabled by default).
# Generate a password by specifying it on the CLI
$ jail_exporter bcrypt foobar
Hash: $2b$12$kSOSps7NIQaEQi2CXb.Ll.qYQZ3pCK7NDWKUH7QvHzprUyLHL6tsq
# Generate a password via an interactive prompt
# The password will be prompted for and then confirmed
$ jail_exporter bcrypt
Password: [hidden]
Hash: $2b$12$/5ghhZFShmhrq5W4tE1hnubk/xgGH0MmixxQeKwSGx0g7kjDFL2hq
# Generate a random password
# The random plaintext password will also be output.
$ jail_exporter bcrypt --random
Password: TiFRz4rg6JHdRunnIFm2aB3uNa0OnlU7
Hash: $2b$12$dyK2iA1Yq1ToA9AWtjg96exmvLABj05DuB1V5a4haUOZvu2.Hvbo2The cost for the password hashing can be controlled with the --cost argument
to the bcrypt subcommand and defaults to 12. This default it taken from the
bcrypt crate and should be tuned for the computer the hashing will be running
on, as this cost will be paid each time a connection is authenticated.
The exporter needs to run as root in order to have enough permission to
execute the rctl_get_racct(2) calls. If it is not run as root, it will
complain and exit.
As jails may come and go during the lifetime of the exporter, so to will the time series that the exporter exports. If you wish to account for resource usage for jails that have disappeared, you may wish to make use of the Prometheus recording rules to track total resource usage across all jails.
The exporter can be run in two different ways. The default way is to run a
persistent network daemon for Prometheus to scrape. The exporter will not
daemonize itself, instead, it is recommended to use a tool such as
daemon(8). See the included rc.d/jail_exporter.in for an example of
this.
The second way is to simply output the scraped metrics to a text file. This
mode is designed to be paired with the node_exporter Textfile Collector.
No port is available yet, but it should happen soon.
This exporter was developed under FreeBSD 11.1 and currently exports all
resources listed under the RESOURCES section of rctl(8).
The id and num time series are calculated based on other information and do
not come from rctl(8) directly. Metric names have their units appended
where appropriate, based on the Prometheus best practice for metric and label
naming.
All exported metrics are prefixed with jail and have a name label
representing the name of the jail. As such, jail names are expected to be
unique.
Descriptions of metrics are taken from the rctl(8) man page where
applicable.
| Metric | rctl(8) name |
Description |
|---|---|---|
coredumpsize_bytes |
coredumpsize |
core dump size, in bytes |
cputime_seconds_total |
cputime |
CPU time, in seconds |
datasize_bytes |
datasize |
data size, in bytes |
maxproc |
maxproc |
number of processes |
memorylocked_bytes |
memorylocked |
locked memory, in bytes |
memoryuse_bytes |
memoryuse |
resident set size, in bytes |
msgqqueued |
msgqqueued |
number of queued SysV messages |
msgqsize_bytes |
msgqsize |
SysV message queue size, in bytes |
nmsgq |
nmsgq |
number of SysV message queues |
nsem |
nsem |
number of SysV semaphores |
nsemop |
nsemop |
number of SysV semaphores modified in a single semop(2) call |
nshm |
nshm |
number of SysV shared memory segments |
nthr |
nthr |
number of threads |
openfiles |
openfiles |
file descriptor table size |
pcpu_used |
pcpu |
%CPU, in percents of a single CPU core |
pseudoterminals |
pseudoterminals |
number of PTYs |
readbps |
readbps |
filesystem reads, in bytes per second |
readiops |
readiops |
filesystem reads, in operations per second |
shmsize_bytes |
shmsize |
SysV shared memory size, in bytes |
stacksize_bytes |
stacksize |
stack size, in bytes |
swapuse_bytes |
swapuse |
swap space that may be reserved or used, in bytes |
vmemoryuse_bytes |
vmemoryuse |
address space limit, in bytes |
wallclock_seconds_total |
wallclock |
wallclock time, in seconds |
writebps |
writebps |
filesystem writes, in bytes per second |
writeiops |
writeiops |
filesystem writes, in operations per second |
| Metric | Description |
|---|---|
exporter_build_info |
The version of Rust used to build the exporter, and the version of the exporter. |
id |
ID of the named jail |
num |
Current number of running jails |
| Feature | Default | Description |
|---|---|---|
auth |
true |
Enables HTTP Basic Authentication |
bcrypt_cmd |
true |
Enables a bcrypt subcommand to assist with hashing passwords for HTTP Basic Authentication |
rc_script |
true |
Enables the --rc-script CLI flag to dump the rc(8) script to stdout |
The rc_script feature is enabled by default for the benefit of users
installing via cargo install. It is disabled by default in the FreeBSD port
as the rc(8) script is supplied in the ports tree.