Introduction

Referring to the Critical vulnerability in Apache Log4j library, about which you can read in the link below will show a simple script with which we will be able to diagnose whether there is log4j on our system.

How check this ?

  • Download script and run
##For Ubuntu
root@master:/home/ozyrys# wget https://gist.githubusercontent.com/spy86/5d701751f3177f612faa21ca46b53f54/raw/2572cf9975da912f7b45e66e6c3a4bb3ac7de245/check_for_ubuntu.sh
root@master:/home/ozyrys# chmod +x check_for_ubuntu.sh
root@master:/home/ozyrys# ./check_for_ubuntu.sh
##For CentOS
root@master:/home/ozyrys# wget https://gist.githubusercontent.com/spy86/73f772de95b73cb4b77d7cca9abdd924/raw/71c98174de0b7cf90d30bf2ac4ddca351a4edf45/check_for_centos.sh
root@master:/home/ozyrys# chmod +x check_for_centos.sh
root@master:/home/ozyrys# ./check_for_centos.sh

Photo by Glenn Carstens-Peters on Unsplash

Command Comparison

Since TSV import is troublesome for both MySQL and PostgreSQL, it is best to create your own script to convert TSV to SQL.

PostgreSQL/MySQL information_schema

Since information_schema is a SQL standard, the same SQL can be used in either case.

Table list

Column list

Setup Default Connection

In PostgreSQL this is set by environment variable

export PGDATABASE = DB name
export PGHOST = host
export PGPORT = port number
export PGUSER = username
export PGPASSWORD = password

The password can also be set with ~/.pgpass

In MySQL we can set all in ~/.my.cnf

[client]
database = DB name
user = username
password = password

Introduction

If you really forget all the options, just type journalctlto see all the saved logs, if a long line is truncated, you can scroll to the right by pressing the arrow keys

Let’s start

View recent messages

root@test:/home/ozyrys# journalctl -e

Detailed information

root@test:/home/ozyrys# journalctl -ex

Monitor logs just like tail -f

root@test:/home/ozyrys# journalctl -f

Show only messages for specific services

root@test:/home/ozyrys# journalctl -u sshd

You can specify the full path of the executable file as in.

root@test:/home/ozyrys# journalctl /usr/sbin/sshd

Display only the end of the log

root@test:/home/ozyrys# journalctl -n 100

Display all messages from startup

root@test:/home/ozyrys# journalctl -b

Photo by israel palacio on Unsplash

Introduction

In this short post I will show you how we can easily expose Jmx in Kubernetes. If we want to temporarily debug our application with JMX the easiest way is forward JMX port from Kubernetes pod to your local PC with kubectl port-forward.

Let’s start

Add JVM options to your application

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.port=5000
-Dcom.sun.management.jmxremote.rmi.port=5000 …

Photo by Panos Sakalakis on Unsplash

Introduction

I will show you how to quickly change the proxy of the browser and the LAN to connect to using the command line.

You need administrator privileges to execute the command .

Preparation

Check Interface Name

netsh interface show interface

Virtual settings

Settings01:

  • Proxy: 10.21.21.100:8080
  • Ip Address: 10.21.21.10
  • Mask: 255.255.0.0
  • Gateway: 10.21.21.1
  • DNS: 10.21.21.200

Settings02:

  • Proxy: 172.10.1.100:9090
  • Ip Address: 172.10.0.10
  • Mask: 255.255.0.0
  • Gateway: 172.10.0.1
  • DNS: 172.10.0.200

Switch to Settings01

Switch to Settings02

Maciej

DevOps Consultant. I’m strongly focused on automation, security, and reliability.

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