As well as providing faster NFS volume mounts,it also eases some other Mac OS docker headaches such as port mapping and ssh key sharing. These are all very promising features and I'd like to give it a go. There is also created one volume, which contains files of MySQL database. This solution prevents loosing data when you turn off your Mac, or just reset docker-machine or this particular container. If you want to read something more about parameters available in docker-compose file, you can just go to docker documentation.
Use volumes Estimated reading time: 15 minutes Volumes are the preferred mechanism for persisting data generated by and used by Docker containers. While are dependent on the directory structure of the host machine, volumes are completely managed by Docker. Volumes have several advantages over bind mounts:. Volumes are easier to back up or migrate than bind mounts. You can manage volumes using Docker CLI commands or the Docker API. Volumes work on both Linux and Windows containers.
Volumes can be more safely shared among multiple containers. Volume drivers let you store volumes on remote hosts or cloud providers, to encrypt the contents of volumes, or to add other functionality. New volumes can have their content pre-populated by a container. In addition, volumes are often a better choice than persisting data in a container’s writable layer, because a volume does not increase the size of the containers using it, and the volume’s contents exist outside the lifecycle of a given container.
If your container generates non-persistent state data, consider using a to avoid storing the data anywhere permanently, and to increase the container’s performance by avoiding writing into the container’s writable layer. Volumes use rprivate bind propagation, and bind propagation is not configurable for volumes. Choose the -v or -mount flag Originally, the -v or -volume flag was used for standalone containers and the -mount flag was used for swarm services. However, starting with Docker 17.06, you can also use -mount with standalone containers. In general, -mount is more explicit and verbose.
The biggest difference is that the -v syntax combines all the options together in one field, while the -mount syntax separates them. Here is a comparison of the syntax for each flag. New users should try -mount syntax which is simpler than -volume syntax. If you need to specify volume driver options, you must use -mount.v or -volume: Consists of three fields, separated by colon characters (:). The fields must be in the correct order, and the meaning of each field is not immediately obvious.
In the case of named volumes, the first field is the name of the volume, and is unique on a given host machine. For anonymous volumes, the first field is omitted. The second field is the path where the file or directory are mounted in the container. The third field is optional, and is a comma-separated list of options, such as ro. These options are discussed below.mount: Consists of multiple key-value pairs, separated by commas and each consisting of a = tuple. The -mount syntax is more verbose than -v or -volume, but the order of the keys is not significant, and the value of the flag is easier to understand.
The type of the mount, which can be, volume,. This topic discusses volumes, so the type is always volume. The source of the mount. For named volumes, this is the name of the volume. For anonymous volumes, this field is omitted. May be specified as source or src.
The destination takes as its value the path where the file or directory is mounted in the container. May be specified as destination, dst, or target. The readonly option, if present, causes the bind mount to be. The volume-opt option, which can be specified more than once, takes a key-value pair consisting of the option name and its value. Escape values from outer CSV parser If your volume driver accepts a comma-separated list as an option, you must escape the value from the outer CSV parser. To escape a volume-opt, surround it with double quotes ( ') and surround the entire mount parameter with single quotes ( '). For example, the local driver accepts mount options as a comma-separated list in the o parameter.
This example shows the correct way to escape the list. $ docker service create -mount 'type=volume,src=,dst=,volume-driver=local,volume-opt=type=nfs,volume-opt=device=:,'volume-opt=o=addr=,vers=4,soft,timeo=180,bg,tcp,rw' -name myservice The examples below show both the -mount and -v syntax where possible, and -mount is presented first. Differences between -v and -mount behavior As opposed to bind mounts, all options for volumes are available for both -mount and -v flags. When using volumes with services, only -mount is supported. Create and manage volumes Unlike a bind mount, you can create and manage volumes outside the scope of any container. Create a volume. $ docker container stop devtest $ docker container rm devtest $ docker volume rm myvol2 Start a service with volumes When you start a service and define a volume, each service container uses its own local volume.
None of the containers can share this data if you use the local volume driver, but some volume drivers do support shared storage. Docker for AWS and Docker for Azure both support persistent storage using the Cloudstor plugin. The following example starts a nginx service with four replicas, each of which uses a local volume called myvol2. $ docker service rm devtest-service Removing the service does not remove any volumes created by the service. Volume removal is a separate step.
![Sharing Sharing](https://docs.docker.com/ee/ucp/images/use-nfs-volume-3.png)
Syntax differences for services The docker service create command does not support the -v or -volume flag. When mounting a volume into a service’s containers, you must use the -mount flag. Populate a volume using a container If you start a container which creates a new volume, as above, and the container has files or directories in the directory to be mounted (such as /app/ above), the directory’s contents are copied into the volume.
The container then mounts and uses the volume, and other containers which use the volume also have access to the pre-populated content. To illustrate this, this example starts an nginx container and populates the new volume nginx-vol with the contents of the container’s /usr/share/nginx/html directory, which is where Nginx stores its default HTML content. The -mount and -v examples have the same end result. $ docker container stop nginxtest $ docker container rm nginxtest $ docker volume rm nginx-vol Use a read-only volume For some development applications, the container needs to write into the bind mount so that changes are propagated back to the Docker host. At other times, the container only needs read access to the data.
Remember that multiple containers can mount the same volume, and it can be mounted read-write for some of them and read-only for others, at the same time. This example modifies the one above but mounts the directory as a read-only volume, by adding ro to the (empty by default) list of options, after the mount point within the container. Where multiple options are present, separate them by commas. The -mount and -v examples have the same result.
$ docker container stop nginxtest $ docker container rm nginxtest $ docker volume rm nginx-vol Share data among machines When building fault-tolerant applications, you might need to configure multiple replicas of the same service to have access to the same files. There are several ways to achieve this when developing your applications. One is to add logic to your application to store files on a cloud object storage system like Amazon S3. Another is to create volumes with a driver that supports writing files to an external storage system like NFS or Amazon S3. Volume drivers allow you to abstract the underlying storage system from the application logic.
For example, if your services use a volume with an NFS driver, you can update the services to use a different driver, as an example to store data in the cloud, without changing the application logic. Use a volume driver When you create a volume using docker volume create, or when you start a container which uses a not-yet-created volume, you can specify a volume driver. The following examples use the vieux/sshfs volume driver, first when creating a standalone volume, and then when starting a container which creates a new volume. Initial set-up This example assumes that you have two nodes, the first of which is a Docker host and can connect to the second using SSH. On the Docker host, install the vieux/sshfs plugin.
$ docker run -d -name sshfs-container -volume-driver vieux/sshfs -mount src =sshvolume,target =/app,volume-opt = sshcmd = test@node2:/home/test,volume-opt = password =testpassword nginx:latest Backup, restore, or migrate data volumes Volumes are useful for backups, restores, and migrations. Use the -volumes-from flag to create a new container that mounts that volume. Backup a container For example, in the next command, we:. Launch a new container and mount the volume from the dbstore container. Mount a local host directory as /backup. Pass a command that tars the contents of the dbdata volume to a backup.tar file inside our /backup directory. $ docker run -rm -volumes-from dbstore2 -v $(pwd):/backup ubuntu bash -c 'cd /dbdata && tar xvf /backup/backup.tar -strip 1' You can use the techniques above to automate backup, migration and restore testing using your preferred tools.
Remove volumes A Docker data volume persists after a container is deleted. There are two types of volumes to consider:. Named volumes have a specific source form outside the container, for example awesome:/bar. Anonymous volumes have no specific source so when the container is deleted, instruct the Docker Engine daemon to remove them. Remove anonymous volumes To automatically remove anonymous volumes, use the -rm option.
For example, this command creates an anonymous /foo volume. When the container is removed, the Docker Engine removes the /foo volume but not the awesome volume.