README.md

Note: This setup is now (2022) superseded by the one in https://gitlab.physik.uni-muenchen.de/Nikolai.Hartmann/xcache-nspawn-lrz

Xcache @ LRZ

This repo tracks the definition file of the singularity container and additional configuration for the xcache image used at LRZ in Munich. It's based on Wei's instructions on github:

https://github.com/wyang007/rucioN2N-for-Xcache

Some instructions by Guenter

(Aug 7, 2018)

See also

https://wiki.physik.uni-muenchen.de/etp/index.php/Xcache_stuff

created /etc/xrootd/auth_db following https://twiki.cern.ch/twiki/bin/view/AtlasComputing/Tier3gXrootdSetup

created /etc/grid-security/xrd/* following https://twiki.cern.ch/twiki/bin/view/AtlasComputing/FAXproxyNew

build new image

Before doing that, yum needs to be installed on the system and the file ~/.rpmmacros needs to be created with the following content:

%_var /var
%_dbpath %{_var}/lib/rpm

The image is build with

singularity build "xcache.$(date +%F).img" xcache.singularity.def

make it used by systemd

ln -s "xcache.$(date +%F).img" xcache.img

start shell w/ xcache

singularity shell -B /etc/xrootd:/etc/xrootd:ro -B /etc/grid-security:/etc/grid-security:ro -B /srv/xcache:/data:rw ~xcache/xcache.img

remove cached files

./rm_cached_file.sh AOD.07709524._000001

will output files to be deleted and asks for confimation

grid-proxy

regularly update via

/etc/cron.hourly/update_xcache-proxy

uses this as long term base-proxy

/root/.globus/base.proxy

create with

baseproxy=$HOME/.globus/base.proxy
grid-proxy-init -cert usercert.pem -key userkey.pem -out $baseproxy -valid 10000:00

Setup git directory on server and push changes

mkdir git-config
cd git-config
git init
git config receive.denyCurrentBranch updateInstead

Then locally add remote and push to server, e.g. (assuming xcache1 is in ssh config)

git remote add xcache1 xcache1:git-config
git push xcache1 <branch-name>

If the pushed branch is checked out on the server and there are no untracked changes this will update the files on the server.

On the server, set the worktree to /

# optionally check out branch, if not default
git checkout <branch-name>
# set worktree to /
git config core.worktree /
# don't track README on the server
git update-index --assume-unchanged /README.md
# clear files, except .git
rm -r *

From now on, pushes to the server will update files in-place (if there are no untracked modifications).

Check status on server, ignoring untracked files

git status -uno

Optionally one can commit on the server and pull the changes down to the local repository. But for that one needs to configure a user name and email (can only be one at at time).

git config user.name "<user-name>"
git config user.email "<user-email>"