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Repairing MySQL multi-master replication

We have 2 servers, server1 is the known good and server2 is the one that is out of synchronisation. Make sure nothing is actively querying server2. You can do this by turning on full query logging and tailing the log file for any queries. mysql> SHOW GLOBAL VARIABLES like 'general_log%' ; +------------------+-------------------------------+ | Variable_name | Value | +------------------+-------------------------------+ | general_log | OFF | | general_log_file | /var/lib/mysql/server2.log | +------------------+-------------------------------+ 2 rows in set (0.

Checking SSL certificate expiry dates

This is just a quick note to save this useful bit of information. I may make in to a script one day or use it in something else. echo ''|openssl s_client -connect localhost:636 2>/dev/null | openssl x509 -noout -enddate | sed 's/^not.*\=//'

Unprivileged standalone instance of MySQL

Small script to run a instance of mysql in my home directory using the binary provided by the OS. Maybe some day I will make it more usable but for the time being it suits my needs. #!/bin/bash MYSQL_HOME=$HOME MYSQL_USER=$USER MYSQL_PORT=13306 ACTION=$1 if [ $ACTION == 'init' ]; then echo "initalising new mysql installation at $MYSQL_HOME/var/lib/mysql" rm -rf $MYSQL_HOME/var/lib/mysql mkdir -p $MYSQL_HOME/var/lib/mysql $MYSQL_HOME/mysql/data $HOME/var/lib/mysql/tmp mysql_install_db --user=$MYSQL_USER --datadir=$MYSQL_HOME/var/lib/mysql/data/ cat < $HOME/.my.cnf [mysqld] user=$MYSQL_USER datadir=$MYSQL_HOME/var/lib/mysql/data log-error=mysqld.

Parallel multi process bash with return codes

Have you ever needed to run a bunch of long running processes from a bash script and get their return codes ? I come across this issue quite frequently in my line of work. The most common one is where i need to run rsync to collect files from many machines then if successful run some other task. Depending on the amount of servers and data this can take several hours to run sequentially and I don’t really like waiting around to check the output so that I can run the next task.

Installing Thrift on Fedora 13 (Goddard)

From Thrift Site - “Thrift is a software framework for scalable cross-language services development. It combines a software stack with a code generation engine to build services that work efficiently and seamlessly between C++, Java, Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, Smalltalk, and OCaml.” When I initially tried to install thrift I had some difficulty because of an error which follows. This error makes you think you need something to do with boost but I am pretty sure the issue was that I was missing gcc-c++

Stunnel in client mode

Stunnel is a quick way on taking a non ssl connection and being able to wrap it in ssl for security stunnel version 4 - Fedora 12/RHEL 5.3 /Centos 5.3 vim /etc/stunnel/stunnel.conf add in client=yes [gmail] accept = connect = then run stunnel stunnel version 3 - Ubuntu 8.10 (I haven’t used newer versions) Ubuntu 8.10 has 2 versions of stunnnel: stunnel3 and stunnel4. They have created a symbolic link from /usr/bin/stunnel -> /usr/bin/stunnel3

Delete single line from file

I quite often need to remove a single line from a file by its line number. The most common use case for me is the known_hosts file when I have reinstalled a system, I have in the past used vim and navigated to the line then removed it. This is all well and good but it gets to be a pain having to do it repeatedly, especially when you manage around 1000 servers and the get rebuilt frequently.

Reinstall CentOS using grub

This post is here mainly because I always forget how to do it. This is one of the simplest ways to reinstall a Centos (will probably work for RHEL and maybe even Fedora) system without needing PXE or physical access to the machine. Make sure that that you have tested you kickstart before you use it and don’t blame me if anything goes wrong. Save the following script and make it executable then run it.

Python HTTPConnection bound to network interface

The web server I use at work are multi homed with the default route being the internal management network. We came across an issue where we wanted make a XMLHTTPRequest for a data feed from another company into our web app. We all know due to cross-site scripting attacks this is no longer possible so we had to write a little proxy script to pull the data and serve it from our own site.

Using external scripts with django models

I have used a few web frameworks over the years but I think I have finally found the one that suits my particular needs. I have played with RoR, Turbo Gears, Catalyst and a couple of others but none have actually made me want to write code instead of hoping that it allows me to write less. That was until I discovered Django. A friend of mine had said he was using for his website it but for some reason I managed to get it stuck in my head that he was using Mambo CMS so I never really paid it much attention.