It's the second time that when my local system (Mac OS) crashes and restarts, I lose the running Docker container of MySQL. By "lose" I mean even docker ps -a doesn't show it. It's vanished.
I am using the official mysql-server docker image (https://hub.docker.com/r/mysql/mysql-server) so luckily the data of /var/lib/mysql is in a volume. And I am lucky that after the loss of the container, the volume is there.
The question is, how can I restore the data (e.g. a mysqldump) out of a Docker volume of /var/lib/mysql?
Step 1: Find and verify the volume
Via docker volume ls you can find the name of the volume. Let's say it's <abcdef>.
Then, via docker run -it --rm -v <abcdef>:/var/lib/mysql busybox ls -l /var/lib/mysql make sure you see the files and the dates of the files matches your recent changes to the lost DB. (credits to this answer)
Optionally, you can create a backup out of this volume via this method.
Step 2: Create a new container, and mount this volume on
Whatever docker run command you are already using to start a MySQL container, add -v <abcdef>:/var/lib/mysql_old to it. It should give you a fresh MySQL container up and running, without any issue. Your data is not loaded there yet, just the files are accessible.
Step 3: Copy and overwrite the MySQL data
Now, go into the shell of that container (e.g. docker exec -it <CONTAINER_NAME> bash) and do ls /var/lib/mysql_old to make sure the files from your volume are there.
Then, do cp -R /var/lib/mysql_old/. /var/lib/mysql (or sudo cp ... depending on the user you got in with) and then chown -R mysql:mysql /var/lib/mysql. (Credits to this tutorial)
Step 4: Restart the container
Exit the container and do docker stop <CONTAINER_NAME> to stop the container. Then start it again via docker start <CONTAINER_NAME>. Voila! It should now be a DB with all your data.
Optionally, if you want to start off with a non-hacked container, you can do docker exec <CONTAINER_NAME> sh -c 'exec mysqldump -uroot -p --databases <DATABASE_NAME>' > dump.sql to get a mysqldump out of it, and import that dump.sql into a fresh new container via docker exec -i <CONTAINER_NAME> sh -c 'exec mysql ' < dump.sql.
Related
I have a Docker container that I've created simply by installing Docker on Ubuntu and doing:
sudo docker run -i -t ubuntu /bin/bash
I immediately started installing Java and some other tools, spent some time with it, and stopped the container by
exit
Then I wanted to add a volume and realised that this is not as straightforward as I thought it would be. If I use sudo docker -v /somedir run ... then I end up with a fresh new container, so I'd have to install Java and do what I've already done before just to arrive at a container with a mounted volume.
All the documentation about mounting a folder from the host seems to imply that mounting a volume is something that can be done when creating a container. So the only option I have to avoid reconfiguring a new container from scratch is to commit the existing container to a repository and use that as the basis of a new one whilst mounting the volume.
Is this indeed the only way to add a volume to an existing container?
You can commit your existing container (that is create a new image from container’s changes) and then run it with your new mounts.
Example:
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5a8f89adeead ubuntu:14.04 "/bin/bash" About a minute ago Exited (0) About a minute ago agitated_newton
$ docker commit 5a8f89adeead newimagename
$ docker run -ti -v "$PWD/somedir":/somedir newimagename /bin/bash
If it's all OK, stop your old container, and use this new one.
You can also commit a container using its name, for example:
docker commit agitated_newton newimagename
That's it :)
We don't have any way to add volume in running container, but to achieve this objective you may use the below commands:
Copy files/folders between a container and the local filesystem:
docker cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH
docker cp [OPTIONS] SRC_PATH CONTAINER:DEST_PATH
For reference see:
https://docs.docker.com/engine/reference/commandline/cp/
I've successfully mount /home/<user-name> folder of my host to the /mnt folder of the existing (not running) container. You can do it in the following way:
Open configuration file corresponding to the stopped container, which can be found at /var/lib/docker/containers/99d...1fb/config.v2.json (may be config.json for older versions of docker).
Find MountPoints section, which was empty in my case: "MountPoints":{}. Next replace the contents with something like this (you can copy proper contents from another container with proper settings):
"MountPoints":{"/mnt":{"Source":"/home/<user-name>","Destination":"/mnt","RW":true,"Name":"","Driver":"","Type":"bind","Propagation":"rprivate","Spec":{"Type":"bind","Source":"/home/<user-name>","Target":"/mnt"},"SkipMountpointCreation":false}}
or the same (formatted):
"MountPoints": {
"/mnt": {
"Source": "/home/<user-name>",
"Destination": "/mnt",
"RW": true,
"Name": "",
"Driver": "",
"Type": "bind",
"Propagation": "rprivate",
"Spec": {
"Type": "bind",
"Source": "/home/<user-name>",
"Target": "/mnt"
},
"SkipMountpointCreation": false
}
}
Restart the docker service: service docker restart
This works for me with Ubuntu 18.04.1 and Docker 18.09.0
Jérôme Petazzoni has a pretty interesting blog post on how to Attach a volume to a container while it is running. This isn't something that's built into Docker out of the box, but possible to accomplish.
As he also points out
This will not work on filesystems which are not based on block devices.
It will only work if /proc/mounts correctly lists the block device node (which, as we saw above, is not necessarily true).
Also, I only tested this on my local environment; I didn’t even try on a cloud instance or anything like that
YMMV
Unfortunately the switch option to mount a volume is only found in the run command.
docker run --help
-v, --volume list Bind mount a volume (default [])
There is a way you can work around this though so you won't have to reinstall the applications you've already set up on your container.
Export your container
docker container export -o ./myimage.docker mycontainer
Import as an image
docker import ./myimage.docker myimage
Then docker run -i -t -v /somedir --name mycontainer myimage /bin/bash
A note for using Docker Windows containers after I had to look for this problem for a long time!
Condiditions:
Windows 10
Docker Desktop (latest version)
using Docker Windows Container for image microsoft/mssql-server-windows-developer
Problem:
I wanted to mount a host dictionary into my windows container.
Solution as partially discripted here:
create docker container
docker run -d -p 1433:1433 -e sa_password=<STRONG_PASSWORD> -e ACCEPT_EULA=Y microsoft/mssql-server-windows-developer
go to command shell in container
docker exec -it <CONTAINERID> cmd.exe
create DIR
mkdir DirForMount
stop container
docker container stop <CONTAINERID>
commit container
docker commit <CONTAINERID> <NEWIMAGENAME>
delete old container
docker container rm <CONTAINERID>
create new container with new image and volume mounting
docker run -d -p 1433:1433 -e sa_password=<STRONG_PASSWORD> -e ACCEPT_EULA=Y -v C:\DirToMount:C:\DirForMount <NEWIMAGENAME>
After this i solved this problem on docker windows containers.
My answer will be little different. You can stop your container, add the volume and restart it. How to do it, follow the steps.
docker volume create ubuntu-volume
docker stop <container-name>
sudo docker run -i -t --mount source=ubuntu-volume,target=<target-path-in-container> ubuntu /bin/bash
You can stop and remove the container, append the existing volume in a startup script, and restart from the image. If the already existing existing partitions do keep the data, you shouldn't experience any loss of information. This should also work the same way with Dockerfile and Docker composer.
eg (solr image).
(initial script)
#!/bin/sh
docker pull solr:8.5
docker stop my_solr
docker rm solr:8.5
docker create \
--name my_solr \
-v "/XXXX/docker/solr/solrdata":/var/solr \
-p 8983:8983 \
--restart unless-stopped \
--user 1000:1000 \
-e SOLR_HEAP=1g \
--log-opt max-size=10m \
--log-opt max-file=3 \
solr:8.5
docker cp /home/XXXX/docker/solr/XXXXXXXX.jar my_solr:/opt/solr/contrib/dataimporthandler-extras/lib
docker start my_solr
file with the second volume
#!/bin/sh
docker pull solr:8.5
docker stop my_solr
docker rm solr:8.5
docker create \
--name my_solr \
-v "/XXXX/docker/solr/solrdata":/var/solr \
-v "/XXXX/backups/solr_snapshot_folder":/var/solr_snapshots \
-p 8983:8983 \
--restart unless-stopped \
--user 1000:1000 \
-e SOLR_HEAP=1g \
--log-opt max-size=10m \
--log-opt max-file=3 \
solr:8.5
docker cp /home/XXXX/docker/solr/XXXXXXXX.jar my_solr:/opt/solr/contrib/dataimporthandler-extras/lib
docker start my_solr
Use symlink to the already mounted drive:
ln -s Source_path targer_path_which_is_already_mounted_on_the_running_docker
The best way is to copy all the files and folders inside a directory on your local file system by: docker cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH
SRC_PATH is on container
DEST_PATH is on localhost
Then do docker-compose down attach a volume to the same DEST_PATH and run Docker containers by using docker-compose up -d
Add volume by following in docker-compose.yml
volumes:
- DEST_PATH:SRC_PATH
I was running mariadb instance on docker windows toolkit. I did a env vaiable change on the mariaDB container using kitematic. Now it has recreated an instance loosing all my database. Is there a way to recover from this ?
Checked if threre are dangling volumes, and there are few
docker volume ls -f dangling=true
Got the data recovered using the dangling volumes.
Approach is as following.
First get the list of dangling volumes.
$ docker volume ls -f dangling=true
DRIVER VOLUME NAME
local 6f79b6329d98379495a284287e32a7a57605483dd7bf7fa19924fb2a98fb1d19
local 47bb077ef6f6df9f56bd30c35eeb45f35e62213d2c50db6f078bfdeeee6698ec
Then mounted it on to a Ubuntu container (so that you can go inside the directory and check what is there, as there is no other way to do this when you are using Docker Tool Box on windows)
$ docker run --name tempContainer1-UBUNTU -v 6f79b6329d98379495a284287e32a7a57605483dd7bf7fa19924fb2a98fb1d19:/var/lib/backup -t -i ubuntu /bin/bash
Then you will be inside the bash of newly created contianer. Go to newly mounted directory and check content
$cd /var/lib/backup
$ls
$aria_log.00000001 aria_log_control ib_buffer_pool ib_logfile0 ib_logfile1 ibdata1 ibtmp1 multi-master.info mysql performance_schema
-- once you are sure directory data is what you require, make a zip file of the folder
$apt-get update
$apt-get install zip
$cd ..
$zip -r backup.zip backup
On another terminal from host copy the content of container backup.zip to host
$docker cp tempContainer1-UBUNTU:/var/lib/backup.zip .
Then create a docker compose file like following and mount the backup folder as data directory. Run this on linux host as this mounting will not work as expected for mysql on windows.
version: "3.2"
services:
mysql:
image: mariadb:10.4.12
restart: always
ports:
- "3306:3306"
command: mysqld --innodb-flush-method=littlesync --innodb-use-native-aio=ON --log_bin=ON
volumes:
- ./backup_data_folder:/var/lib/mysql
environment:
MYSQL_ROOT_PASSWORD: somepassword
TZ: Asia/Singapore
networks:
- frontend
container_name: maria
networks:
frontend:
Start
$docker-compose up
Once it is up, from another terminal go inside newly created container
$docker exec -t -i maria /bin/bash
-- Take dump of all the DBS
$mysqldump -u root -p --all-databases > alldb.sql
Copy content of the dump to host from another terminal from host
$docker cp maria:/alldb.sql .
Now this sql file is a full dump, restore it as usual on your mysql DB or contianer.
mysql -u root -p < alldb.sql
Recently I had to face the same problem for a lost wordpress container and I've followed the instructions from Don. However, as there were lots of dangling volumes, I had to optimize the process. I've managed a way to do it simpler, in the same terminal, resulting in the following steps:
docker volume ls -f dangling=true
DRIVER VOLUME NAME
local 43277666c8bc3da0b585d90952c2303226c92c6c6a561007c0c7ee00b6da817e
local 4fde3ea412e54a1b8b42fce6dae5de5135b9fd12933b020b43bd482cd5fd2225
local 52074ccfd62fb83b8b40cff5f8024215b34f79ad09b630e067ec732f811f798c
...
Then, for each container execute the following instruction, replacing 43277666c8bc3d... with each VOLUME NAME found. This instruction will remove previously maria-restore containers if they exist, create a new one and attach to it:
docker container ls -a -q --filter "name=maria-restore" && docker container rm -f maria-restore; docker run --name maria-restore -v 43277666c8bc3da0b585d90952c2303226c92c6c6a561007c0c7ee00b6da817e:/var/lib/mysql -d mariadb:10.4.12 mysqld --innodb-flush-method=littlesync --innodb-use-native-aio=ON --log_bin=ON && docker exec -it maria-restore bash
If it wasn't a mysql volume, it will fail and exit immediately. If it is a mysql volume, you'll be inside the mariadb container. The database will be already started. You can then connect to the database to see if it is the right one and backup it:
root#8b35c8e2c474:/# mysql -uadmin -p
root#8b35c8e2c474:/# mysqldump -uadmin -p --all-databases > alldb.sql
root#8b35c8e2c474:/# exit
Copy the backed up database:
docker cp mysql-restore:/alldb.sql .
Finally you'll have to clean up the maria-restore container:
docker container ls -a -q --filter "name=maria-restore" && docker container rm -f maria-restore
I know how to restore a dump file from mysqldump. Now, I am attempting to do that using kubernetes and a docker container. The database files are in persistent (nfs) mount. The docker cannot be accessed outside of the cluster as there is no need for anything external to touch it.
I tried:
kubectl run -i -t dbtest --image=mariadb --restart=Never --rm=true --command -- mysql -uroot -ps3kr37 < dump.sql
and
kubectl exec mariadb-deployment-3614069618-mn524 -i -t -- mysql -u root -p=s3kr37 < dump.sql
But neither commands worked -- errors about TTY, sockets, and other things hinting that I am missing something vital here.
What am I not understanding here?
I could just stop the deployment, scp the database files, and restart the container and hope for the best. However, what can go right?
The question Install an sql dump file to a docker container with mariaDB sure looks like a duplicate but is not: first, I am on Linux not Windows and more importantly the answers all are about initialising with a dump. I want to be able to trash the data and revert to the dump data. This is a test system that will eventually be the "live" so I need to restore from many potential dumps.
As described in here you can use the following command to restore a DB on kubernetes pod from a dump in your machine
$ kubectl exec -it {{podName}} -n {{namespace}} -- mysql -u {{dbUser}} -p{{password}} {{DatabaseName}} < <scriptName>.sql
Example :
$ kubectl exec -it mysql-58 -n sql -- mysql -u root -proot USERS < dump_all.sql
What I did was this:
Create an NFS mount with two sub0drectories: mysql and initd.
In initd, I added several ,sql files, including the dump.
Mount initd as /docker-entrypoint-initdb.d in the deployment.This causes all the files to be read at initialisation time provided that it is the first time we run.
The mysql directory is mounted as /var/lib/mysql and contains all the mariaDB files.
If I need to revert, I trash all the contents of the mysql directory and re-create the deployment.
This should work:
kubectl --kubeconfig=k8s-XXXXXXX-kubeconfig.yaml exec -i ddevdb-XXXXX -- mysql -u root -h mysqlservice -proot drupal < you-dump.sql
kubeconfig is optional, digitalocean for examples provides that so you can run your commands from your local.
To see if everything looks good:
kubectl --kubeconfig=k8s-XXXXXXX-kubeconfig.yaml run -it --rm --image=mariadb:10.4 --restart=Never mysql -- mysql -h mysqlservice -proot
After which you'll have a terminal inside mysql.
I'm new in docker, and i have two microservices running in two containers and i would like to create simple database for them.
i created it like that:
docker run --net=kajsnetwork -d -e MYSQL_ROOT_PASSWORD='mypassword' -v /storage/mysql1/mysql-datadir:/var/lib/mysql mysql
i enter the container using
docker exec -it containernumber /bin/bash
and then i created database... But when i went to /var/lib/mysql mysql on host i haven't there nothing new - no database which i created from docker file. Did i something wrong ?
I would like to have database with data stored on host, but running in a docker container (is it good solution?) ? How to do it correctly?
You should not have to docker exec to create an instance: the container should already have one.
The doc mentions:
The -v /my/own/datadir:/var/lib/mysql part of the command mounts the /my/own/datadir directory from the underlying host system as /var/lib/mysql inside the container, where MySQL by default will write its data files.
So the order matters.
The docker cmd option -v /storage/mysql1/mysql-datadir:/var/lib/mysql indicates that you are mounting host directory /storage/mysql1/mysql-datadir to /var/lib/mysql as a data volume of the container.
So if you check /var/lib/mysql from the container your should see the same contents as /storage/mysql1/mysql-datadir in your host machine.
More details:
https://docs.docker.com/engine/tutorials/dockervolumes/#mount-a-host-directory-as-a-data-volume
Tried copying a directory and it doesn't seem to work.
Start a MySQL container.
docker cp mysql:/var/lib/mysql .
cd mysql
ls
NOTHING.
Here's the script to try it yourself.
extra info.
On Ubuntu 14.04
jc#dev:~/work/jenkins/copy-sql/mysql$ docker -v
Docker version 1.2.0, build fa7b24f
In the Dockerfile for the image your container comes from, there is the VOLUME instruction which tells Docker to leave the /var/lib/mysql directory out of the container filesystem.
The docker cp can only access the container filesystem and thus won't see the files in mounted volumes.
If you need to backup your mysql data, I suggest you follow the instructions from the Docker userguide in section Backup, restore, or migrate data volumes. You might also find the discordianfish/docker-backup docker image useful for that task.
Here's a little example to illustrate your case.
given a simple Dockerfile with just a VOLUME instruction
$ cat Dockerfile
FROM base
VOLUME /data
build an image named test
$ docker build --force-rm -t test .
run a container named container_1 which will create two files, one being on the mounted volume
$ docker run -d --name container_1 test bash -c 'echo foo > /data/foo.txt; echo bar > /tmp/bar.txt; while true; do sleep 1; done'
make sure the container is running
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9e97aa18ac83 test:latest "bash -c 'echo foo > 3 seconds ago Up 2 seconds container_1
use the docker cp command to cp file /tmp/bar.txt and check its content
$ docker cp container_1:/tmp/bar.txt .
$ cat bar.txt
bar
try the same with the file which is in the mounted volume (won't work)
$ docker cp container_1:/data/foo.txt .
2014/09/27 00:03:43 Error response from daemon: Could not find the file /data/foo.txt in container container_1
now run a second container to print out the content of that file
$ docker run --rm --volumes-from container_1 base cat /data/foo.txt
foo
It looks like you're trying to pass the name of your container to the docker cp command. The docs say it takes a container id. Try grepping for "CONTAINER ID" in your script instead.
EDIT:
Since changing your script to grep for the Container ID didn't help, you should start by trying this manually (outside of your script).
The docker cp command works. The reason it's not working for you is either:
a permission thing
you're not formatting the command correctly, or
the directory doesn't exist in your container.
With a running container id of XXXX, try this (using your container id):
sudo docker cp XXXX:/var/lib/mysql .
If this doesn't work, and you don't get an error, I'd maybe suggest that that directory doesn't exist in your container.
EDIT2:
As I said, it's one of the 3 things above.
I get this when I run your script:
2014/09/26 16:10:18 lchown mysql: operation not permitted
Changing the last line of your script to prefix with sudo now gives no errors, but no directory either.
Run the container interactively:
docker run -t -i mysql /bin/bash
Once inside the container:
cd /var/lib/mysql
ls
...no files.
So your script is working fine. The directory is just empty (basically #3 above).
For reference, the mysql Dockerfile is here.