Fix connectivity between prometheus and prometheus-node-exporter

Expected to have regressed after https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1008

This patch comes with its own downsides (as described in the comments
for matrix_prometheus_node_exporter_container_http_host_bind_port),
but at least there's:
- no security issue
- metrics remain readable from matrix-prometheus (even if the network metrics are inaccurate)

A better patch is certainly welcome.
This commit is contained in:
Slavi Pantaleev 2021-04-19 18:27:11 +03:00
parent 8da8979a24
commit adcecaffaf
4 changed files with 17 additions and 24 deletions

View file

@ -1701,6 +1701,7 @@ matrix_prometheus_scraper_synapse_targets: ['matrix-synapse:{{ matrix_synapse_me
matrix_prometheus_scraper_synapse_rules_synapse_tag: "{{ matrix_synapse_docker_image_tag }}"
matrix_prometheus_scraper_node_enabled: "{{ matrix_prometheus_node_exporter_enabled }}"
matrix_prometheus_scraper_node_targets: "{{ ['matrix-prometheus-node-exporter:9100'] if matrix_prometheus_node_exporter_enabled else [] }}"
######################################################################
#

View file

@ -19,4 +19,16 @@ matrix_prometheus_node_exporter_systemd_wanted_services_list: []
# Controls whether the matrix-prometheus container exposes its HTTP port (tcp/9100 in the container).
#
# Takes an "<ip>:<port>" value (e.g. "127.0.0.1:9100"), or empty string to not expose.
#
# Official recommendations are to run this container with `--net=host`,
# but we don't do that, since it:
# - likely exposes the metrics web server way too publicly (before applying https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1008)
# - or listens on a loopback interface only (--net=host and 127.0.0.1:9100), which is not reachable from another container (like `matrix-prometheus`)
#
# Using `--net=host` and binding to Docker's `matrix` bridge network may be a solution to both,
# but that's trickier to accomplish and won't necessarily work (hasn't been tested).
#
# Not using `--net=host` means that our network statistic reports are likely broken (inaccurate),
# because node-exporter can't see all interfaces, etc.
# For now, we'll live with that, until someone develops a better solution.
matrix_prometheus_node_exporter_container_http_host_bind_port: ''

View file

@ -25,15 +25,13 @@ ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-prometheus-nod
{% for arg in matrix_prometheus_node_exporter_container_extra_arguments %}
{{ arg }} \
{% endfor %}
--net=host \
--network={{ matrix_docker_network }} \
{% if matrix_prometheus_node_exporter_container_http_host_bind_port %}
-p {{ matrix_prometheus_node_exporter_container_http_host_bind_port }}:9100 \
{% endif %}
--pid=host \
--mount type=bind,src=/,dst=/host,ro,bind-propagation=rslave \
{{ matrix_prometheus_node_exporter_docker_image }} \
{% if matrix_prometheus_node_exporter_container_http_host_bind_port %}
--web.listen-address={{ matrix_prometheus_node_exporter_container_http_host_bind_port }} \
{% else %}
--web.listen-address=localhost:9100 \
{% endif %}
--path.rootfs=/host
ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-prometheus-node-exporter 2>/dev/null'

View file

@ -19,24 +19,6 @@
- "{{ matrix_prometheus_config_path }}"
- "{{ matrix_prometheus_data_path }}"
- block:
# Well, this actually creates the network if it doesn't exist, but..
# The network should have been created by `matrix-base` already.
# We don't rely on that other call and its result, because it runs
# on `--tags=setup-all`, but will get skipped during `--tags=setup-prometheus`.
- name: Fetch Matrix Docker network details
docker_network:
name: "{{ matrix_docker_network }}"
driver: bridge
register: matrix_docker_network_info
# The `matrix_docker_network_info.ansible_facts.docker_network` workaround is for Ansible < 2.8.
# See: https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/907
- set_fact:
matrix_prometheus_scraper_node_targets: ["{{ (matrix_docker_network_info.network|default(matrix_docker_network_info.ansible_facts.docker_network)).IPAM.Config[0].Gateway }}:9100"]
when: "matrix_prometheus_scraper_node_enabled|bool and matrix_prometheus_scraper_node_targets|length == 0"
- name: Download synapse-v2.rules
get_url:
url: "{{ matrix_prometheus_scraper_synapse_rules_download_url }}"