6 merge requests!368Update prace.md to document the change from qprace to qprod as the default...,!367Update prace.md to document the change from qprace to qprod as the default...,!366Update prace.md to document the change from qprace to qprod as the default...,!323extended-acls-storage-section,!196Master,!180Singularity
@@ -9,122 +9,110 @@ Singularity also allows you to leverage the resources of whatever host you are o
* No user contextual changes or root escalation allowed
* No root owned daemon processes
This documentation is for Singularity version 2.4 and newer.
## Using Docker Images
Singularity can import, bootstrap, and even run Docker images directly from [Docker Hub](https://hub.docker.com/). You can easily run RHEL7 like this:
Singularity can import, bootstrap, and even run Docker images directly from [Docker Hub](https://hub.docker.com/). You can easily run RHEL7 container like this:
In this case, image is downloaded from Docker Hub, extracted to a temporary directory and Singularity interactive shell is invoked. This procedure can take a lot of time, especially with large images.
## Importing Docker Image
Singularity containers can be in three different formats:
* read-only **squashfs** (default) - best for production
* writable **ext3** (--writable option)
* writable **(ch)root directory** (--sandbox option) - best for development
Squashfs and (ch)root directory images can be built from Docker source directly on the cluster, no root privileges are needed. It is strongly recomended to create native Singularity image to speed up the launch of the container.
WARNING: Building container as an unprivileged user. If you run this container as root
WARNING: it may be missing some functionality.
Building Singularity image...
Singularity container built: ubuntu.img
Cleaning up...
```
## Launching the Container
The interactive shell can be invoked by the `singularity shell` command. This is useful for development purposes. Use the `-w | --writable` option to make changes inside the container permanent.
```console
hra0031@login4:~$singularity shell -w ubuntu.img
Singularity: Invoking an interactive shell within container...
Singularity image can contain a runscript. This script is executed inside the container after the `singularity run` command is used. The runscript is mostly used to run an application for which the container is built. In the following example it is `fortune | cowsay` command.
```console
hrb33@hrb33-toshiba:/tmp$ssh hrb33@login4.salomon
```
hra0031@login4:~$ singularity run ubuntu.img
___________________
< Are you a turtle? >
-------------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
```
_____ _
/ ____| | |
| (___ __ _| | ___ _ __ ___ ___ _ __
\___ \ / _` | |/ _ \| '_ ` _ \ / _ \| '_ \
____) | (_| | | (_) | | | | | | (_) | | | |
|_____/ \__,_|_|\___/|_| |_| |_|\___/|_| |_|
## Accessing /HOME and /SCRATCH Within Container
http://www.it4i.cz/?lang=en
User home directory is mounted inside the container automatically. If you need access to **/SCRATCH** storage for your computation, this must be mounted by `-B | --bind` option.
!!!Warning
The mounted folder has to exist inside the container or the container image has to be writable!
Last login: Fri Feb 10 14:38:36 2017 from 10.0.131.12
