by Andrew Johnstone
This is something I commonly have to run and always seem to forget. In order to run unattended. Java 6 installation on Ubuntu add-apt-repository “deb http://archive.canonical.com/ $(lsb_release -s -c) partner” apt-get update echo “sun-java6-jdk shared/accepted-sun-dlj-v1-1 select true” | debconf-set-selections echo “sun-java6-jre shared/accepted-sun-dlj-v1-1 select true” | debconf-set-selections DEBIAN_FRONTEND=noninteractive aptitude install -y -f sun-java6-jre sun-java6-bin sun-java6-jdk Java […]
I Spent a little while yesterday investigating why memcached causes problems with multigets returning results and ended up comparing debian vs ubuntu. I tested from virtual machines and physical hardware of relative specs. I have also tried a combination of libmemcached libraries and tuned the tcp stack, however here are some of the results from […]
Currently I have been trying to migrate a 4 node production MySQL database to a blade G5/G7 with vmware ubuntu instances on top of netapp. Typically I would not use a virtual machine nor try to run MySQL on top of NFS, however this needs to fit within the clients infrastructure. Baseline Base line performance […]
One of our clients Gorkana was bought by Durrants. As such I have been working on integrating and merging data. As a result I wrote a script to synchronize data between MySQL and Oracle, which is presently a one way synchronization. The implementation The script(s) to synchronize data was broken into a few scripts. Automatically […]
One of our servers was hacked, 5 days after a Debian Security Advisory. The exploit was executed in two phases, the first to gain access to the system and the second to escalate privileges. The exploit used targeted Exim with a memory corruption issue that allowed a remote attacker to execute arbitrary code as the […]
In: Linux
17 Jul 2010It’s very rare that I setup FTP servers on our production environments and always forget parts of the configuration, so figured I would list it here. Active and Passive FTP There are two types of modes active and passive FTP, using normal or passive FTP, a client initiates a session by sending a request to […]
Recently I started migrating an old server, which had skip-networking within my.cnf, which is not a dynamic option and requires you to restart the mysql server. I typically rsync the source code and static data to a new machine. Configure the webserver with the relevant vhosts and change the database connection details to point to […]
In: Linux
29 May 2010After attaching an EBS volume and rsyncing files to the EBS device the server had a load average of 6 before the server became unresponsive to ssh connections and complained of a broken pipe for ssh. The server was still responding to http requests and ping, however trying to establish a ssh connection, it connected […]
In: Linux
22 May 2010I wrote a few munin plugins to monitor memory, CPU and IO usage per process. After collecting the stats for a few days I noticed that MySQL CPU usage had a constant value of 9.1, however all other processes collected CPU usage correctly.. CPU usage proc=mysqld value=$(ps u -C $proc | awk ‘BEGIN { sum […]
We have re-written parts of the default configuration for ucarp & haproxy to run several VIPs on the same interface. This works on debian, however some minor modifications maybe needed for other distributions. Ucarp implementation /etc/network/if-up.d/ucarp #!/bin/sh UCARP=/usr/sbin/ucarp EXTRA_PARAMS=”” if [ ! -x $UCARP ]; then exit 0 fi if [ -z “$IF_UCARP_UPSCRIPT” ]; then […]
I have been a developer for roughly 10 years and have worked with an extensive range of technologies. Whilst working for relatively small companies, I have worked with all aspects of the development life cycle, which has given me a broad and in-depth experience.