Tag Archives: docker

OpenTelemetry docker demo error for otelcol container

Posted on by
Reply

Problem

You are trying to set up the OpenTelemetry docker demo application but the otel container fails with errors similar to the followng:

Error: failed to resolve config: cannot resolve the configuration: cannot retrieve the configuration: unable to read the file file:/etc/otelcol-config.yml: open /etc/otelcol-config.yml: permission denied


Error: failed to resolve config: cannot resolve the configuration: cannot retrieve the configuration: unable to read the file file:/etc/otelcol-config-extras.yml: open /etc/otelcol-config-extras.yml: permission denied

Solution

Change the permissions to the two configuration files in src/otelcollector to 644 and then stop and start the container.

Following the log file (docker logs -f otel-col) should have something like the following instead of the previous errors:

2024-01-10T14:44:29.062Z	info	service@v0.91.0/telemetry.go:86	Setting up own telemetry...
2024-01-10T14:44:29.063Z	info	service@v0.91.0/telemetry.go:203	Serving Prometheus metrics	{"address": ":8888", "level": "Basic"}
2024-01-10T14:44:29.064Z	info	exporter@v0.91.0/exporter.go:275	Development component. May change in the future.	{"kind": "exporter", "data_type": "logs", "name": "debug"}
2024-01-10T14:44:29.064Z	info	exporter@v0.91.0/exporter.go:275	Development component. May change in the future.	{"kind": "exporter", "data_type": "traces", "name": "debug"}

Failed to start docker.service: Unit is masked

Posted on by
Reply

Problem

Trying to start the docker service after some upgrades fails with the following message:

Failed to start docker.service: Unit is masked.

Solution

It turns out that after upgrading or more specifically removing and then upgrading the docker installation in ubuntu (in this particular case in raspberry 4 with Ubuntu 20.04 installed), results in this error.

A search brings up the following:

https://forums.docker.com/t/failed-to-start-docker-service-unit-is-masked/67413

and from that the following bug post:

https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1844894

So the solution is to run the following to be able to start the docker service (described in the first link above):

sudo systemctl unmask docker
sudo systemctl start docker

Setting up worldPing with Grafana running in docker

Posted on by
Reply

You would like to test worldPing (https://worldping.raintank.io/worldping/) in your local environment for evaluation purposes.

  • Install Grafana with docker as described here (https://grafana.com/docs/grafana/latest/installation/docker/) and give it a name (ie grafana)
  • Login to the grafana container and install the worldPing plugin:
$ docker exec -it grafana /bin/bash
bash-5.0$ grafana-cli plugins install raintank-worldping-app
  • Exit from the container and stop and start it
bash-5.0$ exit
$ docker stop grafana
$ docker start grafana
  • Login to your grafana installation on the browser (localhost:3000) and go to the section for the plugins to find worldPing
  • To be able to enable it you will need an API key from Grafana Cloud, so create a free account (https://grafana.com/signup/starter/connect-account)
  • Create an API key (Security – API Keys – Add API Key)
  • Go back to Grafana web UI and add the API key so you can enable the worldPing. Add an endpoint to check and select the services to check (DNS, Ping, HTTP, HTTPS)
  • Leave it running for a few minutes and check the dashboards afterwards.
  • Remember to Disable if you want to go back to it again in the near future, or Destroy the endpoint if you do not need it anymore.

Cannot create container for service xxx: invalid mode: /path/to/volume/

Posted on by
Reply

Problem

You are trying to use docker-compose to get some services up with docker but you see an error like the following:

Cannot create container for service xxx: invalid mode: /path/to/volume/

Solution

This is more than likely caused by a typo in your yml file, so go back and check carefully for any typos and correct them.

ERROR: Couldn’t connect to Docker daemon at http+docker://localunixsocket – is it running?

Posted on by
Reply

Problem

Using docker-compose up (or build), displays the following error message (even though the same command used to work previously):

ERROR: Couldn't connect to Docker daemon at http+docker://localunixsocket - is it running?

Solution

This is quite possible caused by permissions issue, as one of the folders files that docker is trying to use is owned by a different user/group from the one trying to use the docker-compose commands. Try to find the file/folder with the different permissions and change it to your user name and group, or use change the files by using something like:

chown -R me:me .