Author: Yi Lu
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Redhat Firewall configuration: from iptables to firewalld
ReadTools to manage firewall Packet filter rules in Linux Kernel is managed by an user-space application named iptables in CentOS and RedHat. Since CentOS 7,…
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Log shipping through ELK
ReadA common devops task is build logging pipeline with ELK stack (Elasticsearch, Logstash, Kibana). Suppose the application is written in Java and currently use log4j’s…
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A review of vSphere virtualization technologies
ReadThis post is a summary of VMware’s white paper Introduction to VMware vSphere. ESXi is the hypervisor (virtualization layer) on bare metal servers that abstracts…
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DICOM data encoding
ReadDICOM is a standard for medical imaging exchanges, originally in radiology, but later expanded into other departments where mass imaging data are acquired, such as…
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Linux Admin Basics 3 of 3 – text processing, regex, sed & awk
ReadMost of the text processing can be processed by awk and sed. Sed is non-interactive stream editor that allows you to specify all editing instructions…
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cron and anacron in RedHat Linux (How logrotate works)
ReadCron and anacron We all know cron is a job scheduler. Many admin uses crontab to manage scheduled task. It is also important to know…