NAME¶ch-pull2dir - Pull image from Docker Hub, flatten and unpack it
$ ch-pull2dir IMAGE[:TAG] DIR
DESCRIPTION¶Pull Docker image named IMAGE[:TAG] from Docker Hub and extract it into a subdirectory of DIR. A temporary tarball is stored in DIR.
Sudo privileges are required to run the docker pull command.
This runs the following command sequence: ch-pull2tar, ch-tar2dir. See warning in the documentation for ch-tar2dir.
- print help and exit
- print version and exit
$ ch-pull2dir alpine /var/tmp Using default tag: latest latest: Pulling from library/alpine Digest: sha256:621c2f39f8133acb8e64023a94dbdf0d5ca81896102b9e57c0dc184cadaf5528 Status: Image is up to date for alpine:latest -rw-r--r--. 1 charlie charlie 2.1M Oct 5 19:52 /var/tmp/alpine.tar.gz creating new image /var/tmp/alpine /var/tmp/alpine unpacked ok removed '/var/tmp/alpine.tar.gz'
Same as above, except optional TAG is specified:
$ ch-pull2dir alpine:3.6 /var/tmp 3.6: Pulling from library/alpine Digest: sha256:cc24af836d1377e092ecb4e8f0a4324c3b1aa2b5295c2239edcc7bbc86a9cbc6 Status: Image is up to date for alpine:3.6 -rw-r--r--. 1 charlie charlie 2.1M Oct 5 19:54 /var/tmp/alpine:3.6.tar.gz creating new image /var/tmp/alpine:3.6 /var/tmp/alpine:3.6 unpacked ok removed '/var/tmp/alpine:3.6.tar.gz'
REPORTING BUGS¶If Charliecloud was obtained from your Linux distribution, use your distribution’s bug reporting procedures.
Otherwise, report bugs to: <https://github.com/hpc/charliecloud/issues>
Full documentation at: <https://hpc.github.io/charliecloud>
DOCKER TIPS¶Docker is a convenient way to build Charliecloud images. While installing Docker is beyond the scope of this documentation, here are a few tips.
Understand the security implications of Docker¶Because Docker (a) makes installing random crap from the internet really easy and (b) is easy to deploy insecurely, you should take care. Some of the implications are below. This list should not be considered comprehensive nor a substitute for appropriate expertise; adhere to your moral and institutional responsibilities.
docker equals root¶Anyone who can run the docker command or interact with the Docker daemon can trivially escalate to root. This is considered a feature.
For this reason, don’t create the docker group, as this will allow passwordless, unlogged escalation for anyone in the group.
Images can contain bad stuff¶Standard hygiene for “installing stuff from the internet” applies. Only work with images you trust. The official Docker Hub repositories can help.
Containers run as root¶By default, Docker runs container processes as root. In addition to being poor hygiene, this can be an escalation path, e.g. if you bind-mount host directories.
Docker alters your network configuration¶To see what it did:
$ ifconfig # note docker0 interface $ brctl show # note docker0 bridge $ route -n
Docker installs services¶If you don’t want the service starting automatically at boot, e.g.:
$ systemctl is-enabled docker enabled $ systemctl disable docker $ systemctl is-enabled docker disabled
Configuring for a proxy¶By default, Docker does not work if you have a proxy, and it fails in two different ways.
The first problem is that Docker itself must be told to use a proxy. This manifests as:
$ sudo docker run hello-world Unable to find image 'hello-world:latest' locally Pulling repository hello-world Get https://index.docker.io/v1/repositories/library/hello-world/images: dial tcp 188.8.131.52:443: connection refused
If you have a systemd system, the Docker documentation explains how to configure this. If you don’t have a systemd system, then /etc/default/docker might be the place to go?
The second problem is that Docker containers need to know about the proxy as well. This manifests as images failing to build because they can’t download stuff from the internet.
The fix is to set the proxy variables in your environment, e.g.:
export HTTP_PROXY=http://proxy.example.com:8088 export http_proxy=$HTTP_PROXY export HTTPS_PROXY=$HTTP_PROXY export https_proxy=$HTTP_PROXY export ALL_PROXY=$HTTP_PROXY export all_proxy=$HTTP_PROXY export NO_PROXY='localhost,127.0.0.1,.example.com' export no_proxy=$NO_PROXY
You also need to teach sudo to retain them. Add the following to /etc/sudoers:
Defaults env_keep+="HTTP_PROXY http_proxy HTTPS_PROXY https_proxy ALL_PROXY all_proxy NO_PROXY no_proxy"
Because different programs use different subsets of these variables, and to avoid a situation where some things work and others don’t, the Charliecloud test suite (see below) includes a test that fails if some but not all of the above variables are set.
AUTHOR¶Reid Priedhorsky, Tim Randles, and others
COPYRIGHT¶2014–2018, Los Alamos National Security, LLC
|2018-12-14 19:09 Coordinated Universal Time|