Commit 0cdbe9a4 authored by Fabio Hernandez's avatar Fabio Hernandez
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# Introduction
This document will provide the steb-by-step instructions to configure your computer to use the binary distribution of the LSST software stack using [CernVM FS](
How to configure CernVM FS to use LSST binary distribution
CERN's CernVM FS is a software component which allow you to mount (in read-only mode) a remote software repository, which will appear to your computer as if the software was locally installed. At [CC-IN2P3]( we prepared a binary distribution of LSST stack to be used through CernVM FS. You will find below the procedure for installing CernVM FS and configuring it to use LSST software.
**WARNING** : please bear in mind that this work is experimental. Your feedback on how to improve it is very welcome. Scroll to the end of this document to know how you can provide feedback.
# Expected Benefits
With this method, you need to install and configure CernVM FS only once. Once this is done, when your computer is connected to the network, you will find the available versions of the LSST software stack under the local directory:
This method of distributing the software is particularly useful for individuals: you don't need to install each official LSST software release by hand on your personal computer, but rather to automatically mount and use the binary distributions prepared for your convenience.
Please note that you don't need special privileges to use the LSST software stack distributed in this way: any user on a pre-configured computer can use the software. However, in order to install and configure CernVM FS, a one-time process, you need super-user privileges on the target machine.
# Installation
So far we have tested this installation on both Scientific Linux 6 and Ubuntu 14.04. It may work on other platforms but we haven't verified that.
### Installing on Scientific Linux 6 (64 bits)
To download the software from CERN's repository and install it, as `root` do:
# cd /tmp
# curl -O
# curl -O
# rpm -vi ./cvmfs-2.1.19-1.el5.x86_64.rpm ./cvmfs-keys-1.5-1.noarch.rpm
### Installing on Ubuntu 14.04 (64 bits)
Some packages are necessary or recommended on Ubuntu. To install them do (as `root`):
# apt-get install autofs attr gdb git
Download and install CernVM FS (as `root`):
# cd /tmp
# curl -O
# curl -O
# dpkg -i ./cvmfs-keys_1.5-1_all.deb ./cvmfs_2.1.19_amd64.deb
# Configuration
The configuration of CernVM FS client to use the binary distribution of LSST software served by CC-IN2P3 is a *one-time operation*. It needs to be performed by user `root`.
* Run the utility:
# cvmfs_config setup
After this step, among other things, an unprivileged user `cvmfs` is created in your computer and several configuration files with sensible default values are located under `/etc/cvmfs`.
The next steps modify the default configuration to the specifics of LSST repository hosted by CC-IN2P3.
* Create file `/etc/cvmfs/keys/` with contents:
-----END PUBLIC KEY-----
This text file contains the public key of CC-IN2P3's software repository for LSST. The CernVM FS client running on your machine needs this key to verify that it is talking to the expected server.
* Create the file `/etc/cvmfs/default.local` with contents:
This file tells the CernVM FS client to mount the repository named `` and to use a local disk cache of up to 20.000 MB. By default, the local cache is located at `/var/lib/cvmfs` but you can use another directory on your local disk. For instance, if you wish CernVM FS cache to be located under `/cvmfscache` add the line below:
You can also modify the size of the disk cache CernVM FS should use. Please bear in mind that the current LSST stack (v9.2) requires about 7GB of disk space. As you may want to use a few releases simultaneously we think 20.000MB is a reasonable starting point but feel free to adapt it as you consider suitable for your particular needs.
* Create file `/etc/cvmfs/config.d/` with contents:
* Set the permissions of the files created in the previous steps:
# chmod 0444 /etc/cvmfs/keys/
# chmod 0644 /etc/cvmfs/default.local /etc/cvmfs/config.d/
* Check your configuration by running
# cvmfs_config chksetup
If everything is correct, this utility will print an explicit `OK` in which case you are ready to use LSST software stack. Otherwise, you will be presented with the relevant error message which will hopefully help you finding what's is wrong with your configuration.
* Restart `autofs` service so that it takes into account the modified configuration:
# service autofs restart
If not already done, you may want to configure your machine to start `autofs` at boot time:
# chkconfig autofs on
This is necessary to automatically mount the remote repository under `/cvmfs/` any time you access a file or directory under that namespace.
Now you are ready to use the stack.
# Usage
In order to use the LSST software stack, you need to setup your environment for a specific version for which there is a binary distribution available. For instance, to use LSST v9.2 do:
$ cd /cvmfs/
$ source
Next you can test run the LSST demo, as documented [here](
# Troubleshooting
Please note that in order for this distribution mechanism to work for you, you need your machine to be connected to the network and able to contact CC-IN2P3 server. To check this is the case please do:
$ curl --proxy --head
You should see a line containning `HTTP/1.0 200 OK` which indicates that your machine can talk to the relevant server.
# Frequently Asked Questions
* **How can I provide feedback?**
Your feedback is very welcome. Please feel free to [open an issue](
* **Where can I get more detailed information on CernVM FS?**
The [CernVM FS downloads page]( contains additional information. In addition, you may want to read the [CernVM FS Technical Information]( for more in-depth information on how CernVM FS works.
* **Can I use my remote LSST software distribution while disconnected from the network?**
The CernVM FS client caches all the file metadata and the contents of the accessed remote files in the local disk of your computer. If you have previously used the stack it is likely that the relevant files are locally available in your local disk, in which case, you may work while disconnected. However, we have not tested this thoroughly, so let us know how it works for you.
# Credits
This work was done by Fabio Hernandez from [IN2P3/CNRS computing center]( (Lyon, France) with very valuable help from Vanessa Hammar who set up the CernVM FS server and proxy infrastructure.
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