How to limit the number of available processors
Use boot parameters to limit the number of available processors. There are two distinct boot options that affect the number of available processors. The nr_cpus option which can be used as a hard...
View ArticleHow to install SmokePing on Debian Bullseye
Keep track of network latency using SmokePing on Debian Bullseye. SmokePing instance configured using the following configuration Install and configure SmokePing Update package index. $ sudo apt-get...
View ArticleHow to use docker-compose to setup a WordPress instance
Use docker-compose to instantly setup a development WordPress instance. I will use a local http://127.0.0.127:8080 address, admin user with 9YyO0T9sPqGplvL0 password. Create plugins directory to...
View ArticleHow to leave Hadoop safe mode
The Hadoop cluster enters safe mode during the name node startup till the basic indicators are met and later in case of emergency, which means that the cluster enters read-only mode. The client will...
View ArticleHow to create Hadoop data nodes whitelist
Create Hadoop data nodes whitelist. Display HDFS report. $ hdfs dfsadmin -report Configured Capacity: 63010750464 (58.68 GB) Present Capacity: 52264609737 (48.68 GB) DFS Remaining: 49384169472 (45.99...
View ArticleHow to pretty-print text files inside terminal
Pretty-print text files inside terminal using bat a cat clone with syntax highlighting and Git integration. Install bat utility. $ sudo apt install bat Display help information. $ batcat --help bat...
View ArticleHow to build DokuWiki container with podman
Build DokuWiki container with podman. Project structure. $ tree . ├── configuration │ ├── acl.auth.php │ ├── local.php │ ├── plugins.php │ ├── unit.config.json │ └── users.auth.php └──...
View ArticleHow to create personal tmux configuration
This is an updated blog post to reflect changes over the last five years (especially GitHub issue #1688) as I am still tmux terminal multiplexer on daily basis. Brief description Set default terminal...
View ArticleHow to enable Control Group v2
Enable Control Group v2 for podman to display container’s resource usage statistics. Display Linux distribution. $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:...
View ArticleHow to create custom WordPress post type
Create a custom WordPress post type to keep your ideas in one place. The following example will create Ideas menu entry where you can jot down your ideas. The whole process is really fun. <?php /**...
View ArticleHow to mount HDFS as a local file system
Mount HDFS as a local file system. Beware, it will support only basic file operation at a slower pace, installation is cumbersome, but it works. I will perform the installation on a client machine, but...
View ArticleHow to inspect Hadoop configuration using command-line
Inspect Hadoop configuration using command-line. Hadoop provides a utility to get necessary configuration information. $ hdfs getconf hdfs getconf is utility for getting configuration information from...
View ArticleHow to squash Docker image
Squash Docker image to remove unnecessary layers in case you do not have a need to keep them. Install docker-squash. $ pip install docker-squash Display help information. $ docker-squash --help usage:...
View ArticleHow to save namespace and perform checkpoint
Save namespace on namenode and perform checkpoint on secondary namenode. Namenode Enter safe mode. $ sudo -u hadoop -i hdfs dfsadmin -safemode enter Safe mode is ON Ensure that safe mode is active. $...
View ArticleHow to create Yarn nodes whitelist
Create Yarn nodes whitelist. Display running Yarn nodes. $ yarn node -list 2021-06-06 22:40:12,371 INFO client.RMProxy: Connecting to ResourceManager at resourcemanager.example.org/192.168.8.172:8032...
View ArticleHow to inspect mitigations for CPU vulnerabilities
Inspect mitigations for CPU vulnerabilities. Clone Spectre & Meltdown Checker repository to get “a shell script to assess your system’s resilience against the several transient execution CVEs that...
View ArticleHow to create a new tmux window with a given name
Create a new tmux window with a given name. # create new window and change name bind-key C command-prompt -p "Create window with name:" "new-window; rename-window '%%'" Use prefix key C to provide a...
View ArticleHow to log HDFS operations
Perform HDFS audit logging. Read log4j.properties on namenode to inspect default HDFS audit logging options. $ cat /opt/hadoop/hadoop-3.2.2/etc/hadoop/log4j.properties [...] # # hdfs audit logging #...
View ArticleHow to install standalone ZooKeeper server
Install standalone ZooKeeper server to play with it. Update package index. $ sudo apt update Install GnuPG. $ sudo apt -y install gpg Install Java. $ sudo apt -y install openjdk-11-jre-headless Create...
View ArticleHow to relay all mail to external account
Relay all mail to an external account which can come in handy in your lab environment. I will forward all mail to mail@example.org using mail.example.org server, mail user and mail_token authentication...
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