Dockercloud-agent error: …Error creating default \”bridge\” network:…

Posted on 17 November 2016 by kosmas

Problem

When trying to use the dockercloud-agent with docker you have the following error in the /var/log/dockercloud/agent.log

level=fatal msg="Error starting daemon: Error initializing network controller: Error creating default \"bridge\" network: cannot create network xxx... (docker0): conflicts with network yyy.... (docker0): networks have same bridge name"

Solution

If you remove the file var/lib/docker/network/files/local-kv.db as suggested here, then if you look again at the log files, it should be a message that the docker daemon has been started:

016/11/17 10:30:28 Respawning docker daemon
2016/11/17 10:30:28 Starting docker daemon: [/usr/bin/docker daemon -H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375 --userland-proxy=false --tlscert /etc/dockercloud/agent/cert.pem --tlskey /etc/dockercloud/agent/key.pem --tlscacert /etc/dockercloud/agent/ca.pem --tlsverify]
2016/11/17 10:30:28 Docker daemon (PID:4036) has been started

Clearing unused (dangling) docker volumes

Posted on 15 November 2016 by kosmas

Problem

After you start using and building Docker images, there is a case that there is a lot of space used even after deleting images and containers (a few GB maybe).

Solution

To clean out the volumes that are no longer used (ie dangling) use the following:

sudo docker volume ls -qf dangling=true | xargs -r sudo docker volume rm

Removing Docker containers that have exited

Posted on 14 November 2016 by kosmas

Problem

You would like to clear Docker containers that have been exited and not cleared properly.

Solution

Run the following to find out the containers that have exited and remove them.

sudo docker ps -a | grep 'Exited' | tail -n +1 | awk '{ print $1 }' | xargs sudo docker rm

Get the IP of a running Docker container

Posted on 11 November 2016 by kosmas

Problem

You would like to know the IP for a running Docker container.

Solution

Run the following two commands (taken from here

docker ps

docker inspect container_name | grep IPAddress

MySQL Displaying Query Results Vertically

Posted on 9 November 2016 by kosmas

Problem

When doing a query in MySQL you would like to display the results vertically instead of horizontally as they are much more readable.

Solution

Terminate the query with \G instead of a semicolon (MySQL documentation):

SELECT * FROM users\G

Error response from daemon: conflict: unable to delete xxx (must be forced) – image is referenced in one or more repositories

Posted on 6 November 2016 by kosmas

Problem

Trying to remove some unused docker images that you no longer use with docker rmi image_id you get the following error message:

Error response from daemon: conflict: unable to delete 75d009de0479 (must be forced) - image is referenced in one or more repositories

Solution

Use the following to delete multiple images (ie ubuntu):

docker images ubuntu | tail -n +2 | awk '{ print $1 ":" $2 }' | xargs sudo docker rmi

Mentioned here

M	T	W	T	F	S	S
	1	2	3	4	5	6
7	8	9	10	11	12	13
14	15	16	17	18	19	20
21	22	23	24	25	26	27
28	29	30

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Web notebook about thoughts and discoveries in DevOps, SRE, Software Engineering….

Monthly Archives: November 2016

Dockercloud-agent error: …Error creating default \”bridge\” network:…

Clearing unused (dangling) docker volumes

Removing Docker containers that have exited

Get the IP of a running Docker container

MySQL Displaying Query Results Vertically

Error response from daemon: conflict: unable to delete xxx (must be forced) – image is referenced in one or more repositories