Signed-off-by: Paul van der Linden <mail@paultjuh.org>
12 KiB
PostgreSQL Server Exporter
Prometheus exporter for PostgreSQL server metrics.
CI Tested PostgreSQL versions: 9.4
, 9.5
, 9.6
, 10
, 11
, 12
, 13
Quick Start
This package is available for Docker:
# Start an example database
docker run --net=host -it --rm -e POSTGRES_PASSWORD=password postgres
# Connect to it
docker run \
--net=host \
-e DATA_SOURCE_NAME="postgresql://postgres:password@localhost:5432/postgres?sslmode=disable" \
quay.io/prometheuscommunity/postgres-exporter
Building and running
git clone https://github.com/prometheus-community/postgres_exporter.git
cd postgres_exporter
make build
./postgres_exporter <flags>
To build the Docker image:
make promu
promu crossbuild -p linux/amd64 -p linux/armv7 -p linux/amd64 -p linux/ppc64le
make docker
This will build the docker image as prometheuscommunity/postgres_exporter:${branch}
.
Flags
-
help
Show context-sensitive help (also try --help-long and --help-man). -
web.listen-address
Address to listen on for web interface and telemetry. Default is:9187
. -
web.telemetry-path
Path under which to expose metrics. Default is/metrics
. -
disable-default-metrics
Use only metrics supplied fromqueries.yaml
via--extend.query-path
. -
disable-settings-metrics
Use the flag if you don't want to scrapepg_settings
. -
auto-discover-databases
Whether to discover the databases on a server dynamically. -
extend.query-path
Path to a YAML file containing custom queries to run. Check outqueries.yaml
for examples of the format. -
dumpmaps
Do not run - print the internal representation of the metric maps. Useful when debugging a custom queries file. -
constantLabels
Labels to set in all metrics. A list oflabel=value
pairs, separated by commas. -
version
Show application version. -
exclude-databases
A list of databases to remove when autoDiscoverDatabases is enabled. -
include-databases
A list of databases to only include when autoDiscoverDatabases is enabled. -
log.level
Set logging level: one ofdebug
,info
,warn
,error
. -
log.format
Set the log format: one oflogfmt
,json
. -
web.config.file
Configuration file to use TLS and/or basic authentication. The format of the file is described in the exporter-toolkit repository.
Environment Variables
The following environment variables configure the exporter:
-
DATA_SOURCE_NAME
the default legacy format. Accepts URI form and key=value form arguments. The URI may contain the username and password to connect with. -
DATA_SOURCE_URI
an alternative toDATA_SOURCE_NAME
which exclusively accepts the hostname without a username and password component. For example,my_pg_hostname
ormy_pg_hostname?sslmode=disable
. -
DATA_SOURCE_URI_FILE
The same as above but reads the URI from a file. -
DATA_SOURCE_USER
When usingDATA_SOURCE_URI
, this environment variable is used to specify the username. -
DATA_SOURCE_USER_FILE
The same, but reads the username from a file. -
DATA_SOURCE_PASS
When usingDATA_SOURCE_URI
, this environment variable is used to specify the password to connect with. -
DATA_SOURCE_PASS_FILE
The same as above but reads the password from a file. -
PG_EXPORTER_WEB_LISTEN_ADDRESS
Address to listen on for web interface and telemetry. Default is:9187
. -
PG_EXPORTER_WEB_TELEMETRY_PATH
Path under which to expose metrics. Default is/metrics
. -
PG_EXPORTER_DISABLE_DEFAULT_METRICS
Use only metrics supplied fromqueries.yaml
. Value can betrue
orfalse
. Default isfalse
. -
PG_EXPORTER_DISABLE_SETTINGS_METRICS
Use the flag if you don't want to scrapepg_settings
. Value can betrue
orfalse
. Defauls isfalse
. -
PG_EXPORTER_AUTO_DISCOVER_DATABASES
Whether to discover the databases on a server dynamically. Value can betrue
orfalse
. Defauls isfalse
. -
PG_EXPORTER_EXTEND_QUERY_PATH
Path to a YAML file containing custom queries to run. Check outqueries.yaml
for examples of the format. -
PG_EXPORTER_CONSTANT_LABELS
Labels to set in all metrics. A list oflabel=value
pairs, separated by commas. -
PG_EXPORTER_EXCLUDE_DATABASES
A comma-separated list of databases to remove when autoDiscoverDatabases is enabled. Default is empty string. -
PG_EXPORTER_INCLUDE_DATABASES
A comma-separated list of databases to only include when autoDiscoverDatabases is enabled. Default is empty string, means allow all. -
PG_EXPORTER_METRIC_PREFIX
A prefix to use for each of the default metrics exported by postgres-exporter. Default ispg
Settings set by environment variables starting with PG_
will be overwritten by the corresponding CLI flag if given.
Setting the Postgres server's data source name
The PostgreSQL server's data source name
must be set via the DATA_SOURCE_NAME
environment variable.
For running it locally on a default Debian/Ubuntu install, this will work (transpose to init script as appropriate):
sudo -u postgres DATA_SOURCE_NAME="user=postgres host=/var/run/postgresql/ sslmode=disable" postgres_exporter
Also, you can set a list of sources to scrape different instances from the one exporter setup. Just define a comma separated string.
sudo -u postgres DATA_SOURCE_NAME="port=5432,port=6432" postgres_exporter
See the github.com/lib/pq module for other ways to format the connection string.
Adding new metrics
The exporter will attempt to dynamically export additional metrics if they are added in the future, but they will be marked as "untyped". Additional metric maps can be easily created from Postgres documentation by copying the tables and using the following Python snippet:
x = """tab separated raw text of a documentation table"""
for l in StringIO(x):
column, ctype, description = l.split('\t')
print """"{0}" : {{ prometheus.CounterValue, prometheus.NewDesc("pg_stat_database_{0}", "{2}", nil, nil) }}, """.format(column.strip(), ctype, description.strip())
Adjust the value of the resultant prometheus value type appropriately. This helps build rich self-documenting metrics for the exporter.
Adding new metrics via a config file
The -extend.query-path command-line argument specifies a YAML file containing additional queries to run. Some examples are provided in queries.yaml.
Disabling default metrics
To work with non-officially-supported postgres versions you can try disabling (e.g. 8.2.15)
or a variant of postgres (e.g. Greenplum) you can disable the default metrics with the --disable-default-metrics
flag. This removes all built-in metrics, and uses only metrics defined by queries in the queries.yaml
file you supply
(so you must supply one, otherwise the exporter will return nothing but internal statuses and not your database).
Automatically discover databases
To scrape metrics from all databases on a database server, the database DSN's can be dynamically discovered via the
--auto-discover-databases
flag. When true, SELECT datname FROM pg_database WHERE datallowconn = true AND datistemplate = false and datname != current_database()
is run for all configured DSN's. From the
result a new set of DSN's is created for which the metrics are scraped.
In addition, the option --exclude-databases
adds the possibily to filter the result from the auto discovery to discard databases you do not need.
If you want to include only subset of databases, you can use option --include-databases
. Exporter still makes request to
pg_database
table, but do scrape from only if database is in include list.
Running as non-superuser
To be able to collect metrics from pg_stat_activity
and pg_stat_replication
as non-superuser you have to create functions and views as a superuser, and
assign permissions separately to those.
In PostgreSQL, views run with the permissions of the user that created them so they can act as security barriers. Functions need to be created to share this data with the non-superuser. Only creating the views will leave out the most important bits of data.
-- To use IF statements, hence to be able to check if the user exists before
-- attempting creation, we need to switch to procedural SQL (PL/pgSQL)
-- instead of standard SQL.
-- More: https://www.postgresql.org/docs/9.3/plpgsql-overview.html
-- To preserve compatibility with <9.0, DO blocks are not used; instead,
-- a function is created and dropped.
CREATE OR REPLACE FUNCTION __tmp_create_user() returns void as $$
BEGIN
IF NOT EXISTS (
SELECT -- SELECT list can stay empty for this
FROM pg_catalog.pg_user
WHERE usename = 'postgres_exporter') THEN
CREATE USER postgres_exporter;
END IF;
END;
$$ language plpgsql;
SELECT __tmp_create_user();
DROP FUNCTION __tmp_create_user();
ALTER USER postgres_exporter WITH PASSWORD 'password';
ALTER USER postgres_exporter SET SEARCH_PATH TO postgres_exporter,pg_catalog;
-- If deploying as non-superuser (for example in AWS RDS), uncomment the GRANT
-- line below and replace <MASTER_USER> with your root user.
-- GRANT postgres_exporter TO <MASTER_USER>;
CREATE SCHEMA IF NOT EXISTS postgres_exporter;
GRANT USAGE ON SCHEMA postgres_exporter TO postgres_exporter;
GRANT CONNECT ON DATABASE postgres TO postgres_exporter;
CREATE OR REPLACE FUNCTION get_pg_stat_activity() RETURNS SETOF pg_stat_activity AS
$$ SELECT * FROM pg_catalog.pg_stat_activity; $$
LANGUAGE sql
VOLATILE
SECURITY DEFINER;
CREATE OR REPLACE VIEW postgres_exporter.pg_stat_activity
AS
SELECT * from get_pg_stat_activity();
GRANT SELECT ON postgres_exporter.pg_stat_activity TO postgres_exporter;
CREATE OR REPLACE FUNCTION get_pg_stat_replication() RETURNS SETOF pg_stat_replication AS
$$ SELECT * FROM pg_catalog.pg_stat_replication; $$
LANGUAGE sql
VOLATILE
SECURITY DEFINER;
CREATE OR REPLACE VIEW postgres_exporter.pg_stat_replication
AS
SELECT * FROM get_pg_stat_replication();
GRANT SELECT ON postgres_exporter.pg_stat_replication TO postgres_exporter;
CREATE OR REPLACE FUNCTION get_pg_stat_statements() RETURNS SETOF pg_stat_statements AS
$$ SELECT * FROM public.pg_stat_statements; $$
LANGUAGE sql
VOLATILE
SECURITY DEFINER;
CREATE OR REPLACE VIEW postgres_exporter.pg_stat_statements
AS
SELECT * FROM get_pg_stat_statements();
GRANT SELECT ON postgres_exporter.pg_stat_statements TO postgres_exporter;
Note
Remember to usepostgres
database name in the connection string:DATA_SOURCE_NAME=postgresql://postgres_exporter:password@localhost:5432/postgres?sslmode=disable
Running the tests
# Run the unit tests
make test
# Start the test database with docker
docker run -p 5432:5432 -e POSTGRES_DB=circle_test -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=test -d postgres
# Run the integration tests
DATA_SOURCE_NAME='postgresql://postgres:test@localhost:5432/circle_test?sslmode=disable' GOOPTS='-v -tags integration' make test