Autor(en): Daniel
05.09.12
Deploying a website using Git via SSH remote
Git has a concept of "remotes" (tracked repositories), which allows to have
arbitrary alternate remote locations besides the typical "origin" remote, like "web".
The basic idea is to setup a user on the remote server ($SSH_DEPLOYUSER) which
is allowed to login via SSH (e.g. by adding your public SSH key to the deploy
user's ~/.ssh/authorized_keys file) and will be used to checkout what you want
to deploy.
To accomplish this you have to setup the Git working directory on the server and
add a "post-receive" hook, which will be invoked by Git after you have pushed
to the repository:
Code:
$ mkdir /path/to/repo-checkout | |
$ cd /path/to/repo-checkout | |
$ git init | |
# Create the post-receive file/hook (Ctrl-D to end the input to "cat"): | |
$ cat > .git/hooks/post-receive | |
#!/bin/sh | |
export GIT_DIR=$(pwd) | |
cd .. | |
git checkout -f | |
git submodule update --init --recursive | |
$ chmod +x .git/hooks/post-receive | |
$ git config --add receive.denyCurrentBranch ignore | |
$ chown $SSH_DEPLOYUSER -R . |
On the local side you have to add a "remote" (named "web" in this case):
The final step is to initially push to it (which requires to specify the "refspec" once - following deployments can be done by just doing a "git push web"):
Code:
$ git remote add web ssh://$DEPLOYUSER@host.example.com/path/to/repo-checkout/.git | |
$ git push web +master:refs/heads/master |
These instructions are based on the howto at toroid.org/ams/git-website-howto, but the main difference is that I am not using a "bare" repository here, which would not allow to use Git submodules; submodules require a "full" Git working directory and having a checkout of the repository requires the receive.denyCurrentBranch=ignore setting.
03.06.12
Use hybrid suspend method by default with pm-utils/Linux (suspend to RAM and disk)
There is this nice method of suspending a computer to RAM (which is quick to suspend and resume, but still uses some battery) and after a given amount of time to disk, if it has not been waken up since then (e.g. after 15 minutes).
Ubuntu (and any other distribution using pm-utils) supports this via the pm-utils package and its pm-suspend-hybrid script.
Unfortunately this is not used by default (even hibernation is not available from the menu by default), but only normal suspend.
The following configuration snippet will make pm-utils use the "suspend_hybrid" method instead of "suspend" when being invoked:
You have to create a file like /etc/pm/config.d/00-use-suspend-hybrid and add the following code (e.g. via sudo -e /etc/pm/config.d/00-use-suspend-hybrid):
Code:
# Always use suspend_hybrid instead of suspend | |
if [ "$METHOD" = "suspend" ]; then | |
METHOD=suspend_hybrid | |
fi |
I came up with this solution after having asked for a method to do so at Ask Ubuntu.
This way hybrid suspend will be used automatically if you select e.g. "Suspend" from the menu or close your laptop's lid (both actions call pm-suspend which then gets remapped).
You can configure the amount of time before hibernation (Suspend To Disk) is being invoked with the PM_HIBERNATE_DELAY variable (in seconds), which you can just configure in the same file, too:
Code:
# Always use suspend_hybrid instead of suspend | |
if [ "$METHOD" = "suspend" ]; then | |
METHOD=suspend_hybrid | |
fi | |
PM_HIBERNATE_DELAY=300 # invoke hibernation to disk after 5 minutes (300 seconds) |
You might want to make sure that the hybrid method is supported on your system via the following code. If it says "0" it should work:
Code:
sudo pm-is-supported --suspend-hybrid && echo $? |
Happy suspending.
15.09.11
Disable disk cache in Chromium / Google Chrome
There is no user interface in Google's browser Chrome yet to disable the disk cache, or control its size (version 14 appears to have something in the developer tools section).
But it can be done using command line options when starting the browser, and you can configure this globally for Ubuntu.
The following command line flags will use /dev/null ("the sink") as cache dir, and additionally limits it to 1 byte:
--disk-cache-dir=/dev/null --disk-cache-size=1
(I have tried just --disk-cache-size=0 or 1, but it did not appear to work as expected)
On Ubuntu/Debian, you can just add these flags to the CHROMIUM_FLAGS variable in /etc/chromium-browser/default and it will be used every time when starting Chromium.
The motivation to do this comes from me using a local (intercepting) HTTP proxy with its cache on a RAM disk. Therefore I do not want Chromium to store quite the same retrieved files on disk again.
Additionally, this is a SSD, which is not that happy about being written to in general.
Therefore /tmp is a tmpfs mount already, and the same should be the case for temporary browser files.
25.08.11
Marian - Only Our Hearts To Lose
Offenbar auch ein sehr schönes Album, wo Marek Hemmann mit involviert ist..
24.08.11
Marek Hemmann - In Between
Alleine wegen des Tracks `Gemini` lohnt sich der Kauf dieses Albums schon sowas von..
Nachdem ich es (aufgrund dieses Tracks) heruntergeladen habe, merkte ich auch, dass sich noch mehr meiner last.fm loved tracks darunter befinden.
Kurzum Geilomat!
Selbst wenn man dann beim MP3-Download feststellt, dass aktuelle Linux-Versionen von Amazon nicht mehr unterstützt werden (man kann dann die Tracks einzeln herunterladen).
15.03.11
Script to double/halve OpenVZ resources
The following script allows you to easily double or halve resources in an OpenVZ container.
You would install this script as "/usr/local/bin/vz-double-resources" and also create a symlink named "vz-half-resources" to it (probably also in /u/l/b).
This then allows you to just call "vz-double-resources 123 shmpages" in case you've been notified that there have been shmpages beancounter failures (resource limit has been hit).
This outputs the command to double the bean counter limit, and allows for easy execution by just forwarding the output to "sh", as in "vz-double-resources 123 shmpages | sh -".
Here's the script (available and maintained as/at Gist):
Code:
# cat =vz-double-resources | |
#!/bin/bash | |
| |
VZ="$1" | |
RESOURCE="$2" | |
| |
if [ -z $VZ ] || [ -z $RESOURCE ]; then | |
echo "Usage: $0 VZ RESOURCE" | |
exit 1 | |
fi | |
| |
case $0 in | |
*-double-*) OPERATION="*2" ;; | |
*-half-*) OPERATION="/2" ;; | |
*) echo "Invalid: $0" ; exit 1;; | |
esac | |
| |
echo "# Operation: $OPERATION" | |
| |
# get failures: | |
# awk '$NF ~ /[0-9]*[1-9]$/' /proc/bc/*/resources | |
| |
if [ -f /proc/bc/$VZ/resources ] ; then | |
# uid resource held maxheld barrier limit failcnt | |
| |
resource=$(echo $RESOURCE | tr '[:upper:]' '[:lower:]') | |
awk /$resource/ /proc/bc/$VZ/resources | { | |
read resource held maxheld barrier limit failcnt | |
if [ -n "$resource" ]; then | |
cmd="vzctl set $VZ --$resource $(($barrier $OPERATION)):$(($limit $OPERATION)) --save" | |
echo $cmd | |
exit | |
fi | |
} | |
fi | |
[[ -n "$cmd" ]] && exit | |
if [ -f /etc/vz/conf/$VZ.conf ] ; then | |
value=$(grep -i "^$RESOURCE=" /etc/vz/conf/$VZ.conf) | |
eval $value | |
RESOURCE=$(echo $RESOURCE | tr '[:lower:]' '[:upper:]') | |
resource=$(echo $RESOURCE | tr '[:upper:]' '[:lower:]') | |
value=$(eval echo \$${RESOURCE}) | |
echo $value | { | |
IFS=: read barrier limit | |
cmd="vzctl set $VZ --$resource $(($barrier $OPERATION)):$(($limit $OPERATION)) --save" | |
echo $cmd | |
} | |
else | |
echo "ERROR: container $VZ not found." | |
exit 1 | |
fi |
This is a script I've been using since quite a while (otherwise it would use zsh instead of bash), and have not looked into after creating it.
I just noticed that it is quite useful in general and therefore wanted to make it public.
