Zookeeper Port Forwarding to all servers from local machine

To simply testing with Zookeeper on a remote Kafka cluster, one must connect to the client application ports on the backend.  When the remote Kafka cluster has multiple nodes and behind a firewall and a SSH jump server, the complexity is fairly high.  Note, the SSH jump server is the permitted man in the middle.  […]

License Management via Maven Plugin

Keeping a license current is luckily addressed by the mycila license maven plugin. This plugin scans the project files in src files and updates the files with the license.txt format. To configure the plguin refer to http://code.mycila.com/license-maven-plugin/reports/3.0/format-mojo.html#excludes. To check the current status of the copyrights and see what needs to be updated: mvn com.mycila:license-maven-plugin:check -f […]

Maven Dependency Version Management

To check the version of a dependency (and subsequently all dependencies), and see if there is a need to update the dependency: 1 – Change to cd my-project2 – Run mvn versions:display-dependency-updates3 – Locate the section in the output:[INFO] The following dependencies in Dependency Management have newer versions:[INFO] com.cloudant:cloudant-client ……………………. 2.4.1 -> 2.16.0 4 – […]

Two New Power User Hacks

Tip #1. I learned two new hacks.  – one to regain control and inspect an SSH Session.  Thanks to ServerFault. https://serverfault.com/questions/283129/why-do-consoles-sometimes-hang-forever-when-ssh-connection-breaks ~. – terminate connection (and any multiplexed sessions) ~B – send a BREAK to the remote system ~C – open a command line ~R – request rekey ~V/v – decrease/increase verbosity (LogLevel) ~^Z – […]

FirewallD

Fast commands for enabling firewalld on RHEL7 and CENTOS7. I had to enable these for a secondary control on a project I am on. Check the Status of the Firewall on Each Machine and confirm firewalld is started. systemctl status firewalld ● firewalld.service – firewalld – dynamic firewall daemon    Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor […]

VirtualBox Additions missing

If you see Kernel Headers not found for target kernel level when installing the VBoxLinuxAdditions.run “Please install them and execute”. This issue was found on centos. You’ll see the commands below: yum install “kernel-devel-uname-r ==$(uname -r)” References https://unix.stackexchange.com/questions/232147/your-kernel-headers-for-kernel-3-10-0-229-el7-x86-64-cannot-be-found

Kerberos and Java

I have worked on a kerberos smoke test for my team. I learned a few tips in the process. The useTicketCache is a preferred use in case the java process dies while the KDC is down. HBase Canary Testing runs on a kerberos enabled cluster using hbase canaryhttp://hbase.apache.org/book.html#trouble.client If you are port forwarding over SSH, […]

Forwarding DGram in node.js

For a project I am working on I needed to rewrite a DGram port. I moved the ports around and found a few quick tests. Testing with NC my-machine:~$ echo -n “data-message” | nc -v -4u -w1 localhost 88found 0 associationsfound 1 connections:1: flags=82<CONNECTED,PREFERRED> outif (null) src 127.0.0.1 port 53862 dst 127.0.0.1 port 88 rank […]