Does anyone have a working trivial example of a Dockerfile & command line that mount an external directory from linux into the docker image? -

all i'm looking dockerfile & docker build+run commands on linux view /var/tmp via mount point within container. issues here complicated cases or involve os/x & windows or trying more mount volume. case i've tried mount /var/tmp onto /foobar of busybox image, run container image, , use "ls /foobar" see contents.

running "docker version 1.6.1, build 97cd073" on linux 4.0.1 w/ aufs using local repostory.

http://docs.docker.com/userguide/dockervolumes/

notes that:

mount host directory data volume  in addition creating volume using  -v flag can mount directory  docker daemon's host container.  <snip>  $ sudo docker run -d -p --name web -v /src/webapp:/opt/webapp  training/webapp python app.py  mount host directory, /src/webapp,  container @ /opt/webapp.      note: if path /opt/webapp exists      inside container's image, contents      replaced contents of      /src/webapp on host stay consistent      expected behavior of mount  useful testing, example can mount our source  code inside container , see our application @ work change  source code. directory on host must specified  absolute path , if directory doesn't exist docker  automatically create you. 

i'm using local repository acquires "/data" directory via "-v" switch docker run:

docker run -d -p 5000 \ -v '/var/lib/docker/registry:/data/registry/storage' \ 'kampka/registry'; 

this seems work hosts's /var/lib/docker/registry directory gets entries added it.

so try simple test myself: build minimal copy of busybox access /var/tmp on host system.

from        localhost:5000/lembark/busybox maintainer  lembark@wrkhors.com  volume  [ "/foobar" ]  env     path /bin workdir /  entrypoint  [ "/bin/sh" ] 

at point running "docker build" executes volume command, not create mount point:

$ docker build --tag="localhost:5000/lembark/hak" . ;  sending build context docker daemon  7.68 kb sending build context docker daemon step 0 : localhost:5000/lembark/busybox  ---> c1a1f5abbf79 step 1 : maintainer lembark@wrkhors.com  ---> using cache  ---> b46677881767 step 2 : volume /foobar  ---> running in 7127bdbcfb56  ---> bcf9c3f1c441 removing intermediate container 7127bdbcfb56 step 3 : env path /bin  ---> running in 89f92c815860  ---> 780fea54a67f removing intermediate container 89f92c815860 step 4 : workdir /  ---> running in aa3871c408a1  ---> 403190e9415b removing intermediate container aa3871c408a1 step 5 : entrypoint /bin/sh  ---> running in 4850561f7ebd  ---> 77c32530b4a9 removing intermediate container 4850561f7ebd built 77c32530b4a9 

the "volume /foobar" in step 2 seems indicate mount point should available @ runtime.

at point using either of

docker run --rm -t -i                     localhost:5000/lembark/hak; docker run --rm -t -i -v /foobar          localhost:5000/lembark/hak; docker run --rm -t -i -v /var/tmp:/foobar localhost:5000/lembark/hak; 

leaves me with:

# ls -al /foobar ls: /foobar: no such file or directory 

adding mkdir before volume leaves me /foobar directory anonymous volume, not mapping /var/tmp:

...  run     [ "mkdir", "/foobar" ] volume  [ "/foobar" ] 

or

# made local ./foobar directory, added image.  copy    [ "foobar", "/foobar" ] 

bofh of these leave /foobar, no way map external directory it. instead keep getting anonymous volumes:

 # mount | grep foobar;  /dev/mapper/vg00-var--lib on /var/lib/docker/aufs/mnt/dd12f3e11a6fcb88627412a041b7c910e4d32dc1bf0c15330899036c59d7b3d9/foobar type xfs (rw,noatime,nodiratime,attr2,inode64,logbufs=8,logbsize=256k,logdev=/dev/vg02/var-lib-extlog,noquota) 

no combination or without each of mkdir, volume, copy, or -v leaves me viewing /var/tmp undef /foobar.

thanks

this works me

dockerfile

from busybox:latest volume /foo/bar 

command

$ docker build -t bb . sending build context docker daemon 2.048 kb sending build context docker daemon step 0 : busybox:latest  ---> 8c2e06607696 step 1 : volume /foo/bar  ---> running in a94615dd3353  ---> fa500ba91831 built fa500ba91831 $ docker run -it -v /tmp:/foobar bb ls /foobar [contents of /tmp directory] 

note don't need volume command this. docker run -it -v /tmp:/foobar busybox:latest ls /foobar works well.