Logrotate is a linux utility which rotates files upon certain conditions.If it's not installed, you can do via apt-get install logrotate or yum install logrotate The usual tricky part of logrotate is to reload the process when rotation is complete. Here I'm storing a few logrotate configurations which are

AWS autoscaling groups let you manage a set of instances and scale them in or out, based on various parameters. Deployment strategy: To launch new instances with latest code version and deprecate old ones once newer are working. Deployment to AWS Autoscaling group is seamless if we're using code deploy.

To move a sub-directory/folder to other git repo. Let's leave the usual working directory as is, and create new directory for this experiments. Go to new directory, let's say ~/parallel-universe. sun/ fossil/ dinousar tardigrades chemicals/ energy/ .git/ earth/ Steps: cd ~/parallel-universe/ git clone [email protected]:universe/sun.git

Note: This was way before cloud evolved to provided increase of size from their API or console. This shouldn't be necessary. Often, we end up adding disks to increase space. However, we have to mount them on a new partition. Change our data modules everywhere. Ex: Mongo disk is originally

To check ulimit (which generally causes too many files open error), don’t use ulimit -n ulimit of each process varies and when you issue the command, it’s issued by shell you’re logged in. Instead, to check process’ pid, you should use cat /proc//limits You can get

Opened a file in vi without sudo. Edited some stuff, realized you can't save it. You close the file, open with sudo, redo the edits. How about, switching to sudo while vi is still open? Here's what you got to do: 1. Open file and edit normally. vi filename 2.

Here's the command to understand where is it running slow and what's happening at each step. set -x; GIT_TRACE=2 GIT_CURL_VERBOSE=2 GIT_TRACE_PERFORMANCE=2 GIT_TRACE_PACK_ACCESS=2 GIT_TRACE_PACKET=2 GIT_TRACE_PACKFILE=2 GIT_TRACE_SETUP=2 GIT_TRACE_SHALLOW=2

On workstation knife node delete --yes NODENAME knife client delete --yes NODENAME On client yum -y remove chef rm -rf /var/chef rm -rf /etc/chef rm -rf /opt/chef Bootstrap again, if needed.

mysqld --help --verbose will show variables that'd be loaded if process mysqld (re)started. This will also throw errors if config file /etc/my.cnf is invalid. To get variables of current running process, login to mysql shell and run show variables

sudo service mysqld stop sudo su - mysql /usr/sbin/mysqld --skip-grant-tables --skip-networking & mysql -u root > flush privileges > SET PASSWORD FOR root@'localhost' = PASSWORD('myn3wpa$$word'); > quit exit sudo service mysqld start

1. Login to existing mysql server. 2. Change the configuration /etc/my.cnf, add the following server-id=1, log-bin=mysql-bin 3. To make sure your configuration is correct, run mysqld --verbose 4. For the mysql process to pick up these, you need to run sudo service mysql restart and verify

Git commits aren't the perfect way to communicate change logs, however it gets better each phase. Phase 1: Tell developers to add #changelog in their commit messages, if they want a message to go as a change log. Release notes post deployment can be generated with the command: git log

No-nonsense steps: Backup mechanism: 1. Tag volumes of the attached instance with appropriate volume_group names. 2. For each volume group, take lvm snapshot 3. For each ebs in the volume group, take ebs snapshot. 4. Delete lvm snapshot as soon as ebs snapshot process started. 5. Tag ebs snapshots

To find number of unique connections per IP address, sorted from max to min: netstat -antu | grep :80 | grep -v LISTEN | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -rn To exclude localhost connections, add grep -v 127.0.0.1 in the end.

aws cloudwatch put-metric-alarm --alarm-name "application-name-cpu" --metric-name CPUUtilization --namespace AWS/EC2 --statistic Average --period 300 --threshold 80 --comparison-operator GreaterThanThreshold --dimensions "Name=InstanceId,Value=i-******" --alarm-actions arn:aws:sns:us-east-1:account_number:topic_name --unit Percent --evaluation-periods 2

To find top 10 files eating up disk space -- du -kh |sort -nr |head -10 To find disk space per folder/file in current directory. -- du -sch .[!.]* * |sort -h To find deleted files still being accessed by any processes -- lsof +L1 If df looks fine, yet no

If you're proxying from nginx to an ELB endpoint, either CNAME or a DNS entry, you'd most likely end up in an issue where nginx sometimes sends the requests to an unknown IP. Below is an example config of nginx proxy passing to an ELB when it receives a request

Every file and directory in linux have their own permissions. They decide what a user can do with them, inform the same to system. In a nutshell, a file/directory lets a user do either of: read (r), write (w) and execute (x). For files: * read -- user can read

Generic 1. What is Recursion [http://stackoverflow.com/a/717839/3834860] 2. What is Ptrace [http://askubuntu.com/questions/146160/what-is-the-ptrace-scope-workaround-for-wine-programs-and-are-there-any-risks] CSS/HTML 1. FAQ toggle style css [http://www.cssmojo.com/toggle_elements/] Google app script 1. Customize email to customer who filled the form [https://developers.google.com/

Ensure that there's no process running by the user you're modifying. ps aux|grep oldname should show you only one result which is grep itself. Login to root or use any other sudo user (you can't change name of the user you currently logged in, as login itself is a