Using an Undisciplined Local Clock to Cause NTPD to Exit/Panic, and How to Recover from It

NTP is the protocol used to ensure that the clocks in our hosts are synchronized despite experiencing "drift" over time. Our hosts sync with one or more public time servers, and can in turn act as local time servers for a network. There are best practices on how to go about this, as mentioned in … Continue reading Using an Undisciplined Local Clock to Cause NTPD to Exit/Panic, and How to Recover from It

PostgreSQL 11 Warm Standby Failover (Synchronous Streaming Replication) for High Availability in Docker

This post is part of a series of PostgreSQL Standby Failover in Docker: Cold Start Failover Warm Standby Failover (Log Shipping) Warm Standby Failover (Asynchronous Streaming Replication) Warm Standby Failover (Synchronous Streaming Replication) The PostgreSQL documentation has a high level overview on how to set up various failover, replication, and load balancing solutions (link). I found … Continue reading PostgreSQL 11 Warm Standby Failover (Synchronous Streaming Replication) for High Availability in Docker

PostgreSQL 11 Warm Standby Failover (Asynchronous Streaming Replication) for High Availability in Docker

This post is part of a series of PostgreSQL Standby Failover in Docker: Cold Start Failover Warm Standby Failover (Log Shipping) Warm Standby Failover (Asynchronous Streaming Replication) Warm Standby Failover (Synchronous Streaming Replication) The PostgreSQL documentation has a high level overview on how to set up various failover, replication, and load balancing solutions (link). I found … Continue reading PostgreSQL 11 Warm Standby Failover (Asynchronous Streaming Replication) for High Availability in Docker

PostgreSQL 11 Warm Standby Failover (Log Shipping) for High Availability in Docker

This post is part of a series of PostgreSQL Standby Failover in Docker: Cold Start Failover Warm Standby Failover (Log Shipping) Warm Standby Failover (Asynchronous Streaming Replication) Warm Standby Failover (Synchronous Streaming Replication) The PostgreSQL documentation has a high level overview on how to set up various failover, replication, and load balancing solutions (link). I found … Continue reading PostgreSQL 11 Warm Standby Failover (Log Shipping) for High Availability in Docker

Using One SSH Key Pair Across Multiple Network Zones

Reminder: All views expressed on this blog are my own, and are not representative of any organization I was/am affiliated with.  Overview Secure Shell (SSH) is an encrypted protocol that is commonly used for communication between hosts on an unencrypted network. Connecting to another host on the network comprises of connecting to its SSH server, … Continue reading Using One SSH Key Pair Across Multiple Network Zones

Finding Postgres pg_hba.conf File

The pg_hba.conf file is the PostgreSQL Client Authentication Configuration File, aka the Host Based Authentication File. Depending on your distro/system, it may be installed in different locations. One easy way to find it would be to issue the following command from the psql command line: psql > SHOW hba_file; This command will show you the … Continue reading Finding Postgres pg_hba.conf File

Installing Appian 17.4 on CentOS 7

Appian 17.4 was released on 17th November 2017, and is the final quarterly release in 2017. More information of the release can be found here: https://www.youtube.com/watch?v=k1868iUYIco) This post will describe the installation steps I took to get Appian 17.4 running on a clean installation of CentOS 7. I previously did a guide for Appian 17.2 - … Continue reading Installing Appian 17.4 on CentOS 7

Shell Script – Kill Application Processes After X Minutes

I recently wrote a script to terminate processes of a particular application if it has been running for more than or equals to X minutes. Do note that for this script, the "running" time of an application refers to the difference between the current time and the process creation time. The motivation behind this was … Continue reading Shell Script – Kill Application Processes After X Minutes

Installing Appian 17.2 on Centos 7

As part of a recent project, I was provided the opportunity to evaluate Appian (a Business Process Management Suite) and how it can fit the requirements. As part of the exploratory phase, I had to understand Appian's architecture and install an evaluation instance. This post will describe the installation steps I took to get Appian … Continue reading Installing Appian 17.2 on Centos 7