I'm definitely new to docker at all, started to use it a while ago and I need to move my stuff from one server to another. I thought that just creating a personal image will solve this issue, but nope :D.
So if I'm right, all data is saved on created volume, right? Like one of the containers is PostgreSQL.
So to move everything i need also backup the volume and export it on a new server?
https://docs.docker.com/storage/volumes/#backup-restore-or-migrate-data-volumes
This is what I found on their docs.
Hope somebody could help me with understanding
Docker, for default, stored images, containers, volumes, and other data, into /var/lib/docker, if not customized by the file /etc/docker/daemons.json as explained here.
In order to move all the graph to a new server you should:
Stop docker service.
Copy data root.
Restart docker service.
Regards.
Related
I have taken some time to create a useful Docker volume for use at work. It has a restored backup of one of our software databases (SQL Server) on it, and I use it for testing/debug by just attaching it to whatever Linux SQL Container I feel like running at the time.
When I make useful Docker images at work, I share them with our team using either the Azure Container Registry or the AWS Elastic Container Registry. If there's a DockerFile I've made as part of a solution, I can store that in our GIT repo for others to access.
But what about volumes? Is there a way to share these with colleagues so they don't need to go through the process I went through to build the volume in the first place? So if I've got this 'databasevolume' is there a way to source control it? Or share it as a file to other users of Docker within my team? I'm just looking to save them the time of creating a volume, downloading the .bak file from its storage location, restoring it etc.
The short answer is that there is no default docker functionality to export the contents of a docker volume and docker export explicitly does not export the contents of the volumes associated with the container. You can backup, restore or migrate data volumes.
Note: if your're backing up a database I'd suggest using the appropriate tools for that database.
I am new to docker. So what I want to have is a pgadmin container which I can pull and have always my configs and connections up to date. I was not really sure how to do that, but can I have a Volume which is alsways shared for example on my Windows PC at home and on work? I couldt find an good tutorial for that and dont know if that makes sense. Lets say my computer would be stolen I just want to install docker and my images and fun.
What about a shared directory using DropBox ? as far as i know that the local dropbox directories always synced with the actual dropbox account which means you can have the config up to date for all of your devices.
Alternatively you can save the configuration - as long as it does not contain sensitive data - on a git repository which you can clone it then start using it. Both cases can be used as volumes in docker.
That's not something you can do with Docker itself. You can only push images to DockerHub, which do not contain information that you added to a container during an execution.
What you could do is using a backup routine to S3 for example, and sync your 'config and connections' between your docker container running on your home PC and work one.
I am learning CDH and Docker and didn't have prior experiene in setting up both tools. After reading documentation i managed to run CDH docker in mac environment and also completed example given in quick start guid. But when next day when i started mac book again to learn something new but i didn't find my previous work which i found very strange and even couldn't see container running which seems fine to me.
What i really want to do is i don't want to loose my work even after stoping docker container. could you please guid me how do i configure docker so that i will not loose my work even after restarting docker again?
Every instance of a docker run will allocate a new filesystem, essentially starting from scratch.
If you actually want to "save" your work, then you need to volume mount (using -v docker flag) your local filesystem into the container for at least the following directories.
HDFS Data Directory
NameNode Data Directory
/home/cloudera
I think the hadoop data folders are somewhere under /var/lib/hadoop-*, by default
The better alternative for saving your workloads would be the CDH VM, where it actually has a persistent HDD associated with it.
I have two hosts and docker is installed in each.
As we know, each docker stores the images in local /var/lib/docker directory.
So If I want to use some image, such as ubuntu, I must execute the docker pull to download from internet in each host.
I think it's slow.
Can I store the images in a shared disk array? Then have some host pull the image once, allowing every host, with access to the shared disk, to use the image directly.
Is it possible or good practice? Why docker is not designed like this?
It may need to hack the docker's source code to implement this.
Have you looked at this article
Dockerizing an Apt-Cacher-ng Service
http://docs.docker.com/examples/apt-cacher-ng/
extract
This container makes the second download of any package almost instant.
At least one node will be very fast, and I think it should possible to tell the second node to use the cache of the first node.
Edit : you can run your own registry, with a command similar to
sudo docker run -p 5000:5000 registry
see
https://github.com/docker/docker-registry
What you are trying to do is not supposed to work as explained by cpuguy83 at this github/docker issue.
Indeed:
The underlying storage driver would need to synchronize access.
Sharing /var/lib/docker is far not enough and won't work!
According to the doc.docker.com/registry:
You should use the Registry if you want to:
tightly control where your images are being stored
fully own your images distribution pipeline
integrate image storage and distribution tightly into your in-house development workflow
So I guess that this is the (/your) best option to work this out (but I guess that you got that info -- I just add it here to update the details).
Good luck!
Update in 2016.1.25 docker mirror feature is deprecated
Therefore this answer is not applicable now, leave for reference
Old info
What you need is the mirror mode for docker registry, see https://docs.docker.com/v1.6/articles/registry_mirror/
It is supported directly from docker-registry
Surely you can use public mirror service locally.
So I'm still trying to figure out what would be the best way to use docker in my current infrastructure.
I've been thinking of creating a data-volume containers, that containers would hold the data volume for mongodb (this seem to be pretty popular approach).
If I do that, how would I update the container without loosing the data inside it?
========== EDIT ==========
Clarification:
I want to be able to "update" the container by, basically, rebuilding from Dockerfile. This means that I'll need to spin up a new container, but I want to keep the volumes from the old one
I think this might help you:
https://github.com/discordianfish/docker-backup
TL;DR: You just need to ensure that another container (such as: backup_monitor) is referencing the data volume and you will keep the volumes no matter what. Whether you rebuild your container or not, data volumes are meant to bypass the Union File System so it are kept while there is some container pointing to it.
Another approach could be to share the data volumes with the docker host, using this way you can forget about data because is saved on the host directly. Hope it helps.