Journey of an IT Architect

  • Docker Compose, Docker Stack and Docker Swarm

    This posting covers some basic docker orchestration tools. Docker Compose Docker Compose’s predecessor is a tool called Fig developed by Orchard, which was acquired by…

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  • Ansible at scale 1 of 2

    The Ansible In Depth white paper outlines Ansible’s use cases in four categories: Configuration management Application deployment Orchestration: for coordinating a multi-machine process such as…

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  • Balloon steals memory from virtual machines

    This article is my experience with memory balloon on virtual machine. I came across an ElasticSearch server (ESXi guest with 32GB physical memory) where the…

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  • Cassandra data model (as opposed to relational model)

    Bad data model design with Cassandra causes chronic pains as application scales. I had to re-read about data model design in “Cassandra – the Definitive…

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  • How memory usage adds up in Linux

    There are too many metrics that describes some aspects about memory in Linux. This posting will make sense of those common metrics in Linux, CentOS…

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  • Common local Git operations

    This is a summary of concepts in common Git operations. We will discuss brach, merge, rebase, cherrypick, stash and reset. Then we’ll discuss pull, fetch,…

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