Monitoring HikariCP Metrics Without Micrometer or OpenTelemetry

You can quickly monitor HikariCP connection pool metrics without enabling Micrometer or OpenTelemetry. Just follow these two simple steps:

1. Enable Debug Logging in logback-spring.xml. Add one of the following logging configurations: 

For general Hikari pool logging:

<logger name="com.zaxxer.hikari.pool.HikariPool" level="DEBUG" />

For more detailed logging:

<logger name="com.zaxxer.hikari" level="DEBUG" />

2. Set the Housekeeping Interval via VM Option Set the following JVM option to adjust the logging frequency (default is 30s; this reduces it to 5 seconds):

-Dcom.zaxxer.hikari.housekeeping.periodMs=5000

Example Log Output 

Once enabled, you’ll start seeing logs like this:

2025-03-29 16:30:07,869 DEBUG c.z.h.p.HikariPool[HikariPool-1 housekeeper] - HikariPool-1 - Pool stats (total=2, active=0, idle=2, waiting=0)

Breakdown of Pool Stats: 

• total=2 - The total number of connections in the pool (both active and idle). 
• active=0 - The number of connections currently in use (0 means no connections are being used). 
• idle=2 - The number of available (idle) connections that are not in use. 
• waiting=0 - The number of threads waiting for a connection (0 means no requests are waiting). 

By enabling this, you get real-time insights into your connection pool without additional monitoring tools.

How to Modify a File Inside a Running Docker Container

Let's assume we need to modify the file logback-spring.xml inside the container bb9d1daac389.

docker exec -it bb9d1daac389 sh
# cd /app
# vim logback-spring.xml
/bin/sh: 1: vim: not found
# apt update
# apt install vim
# vim logback-spring.xml

If the container is not based on an Ubuntu image, you can check the OS using cat /etc/os-release and use the corresponding package manager, such as apt, pacman, or another appropriate tool.

Kitty SSH Issue: No Output in top and htop Error

With Kitty, the top command in SSH shows nothing. I tried htop, but it returned an error.

What I did: Googled the issue and looked for a better solution.

Solution 1: Directly in the SSH terminal session:

TERM=xterm top

Solution 2: Add to local .ssh/config file

SetEnv TERM=xterm

Import VPN config files into NetworkManager from the command line

nmcli connection import type openvpn file vpn-config.ovpn

How to check battery status in CLI on Linux?

Option 1

cat /sys/class/power_supply/BAT0/capacity

Option 2: install the package acpi and

acpi -i

Sources:

How do I check the battery's status via the terminal?

How to Check Battery Status Using Linux Command Line

One conclusion as a project manager

Before my experience as a project manager, I had thought that you knew the details of how to perform a task only if you had implemented it yourself. However, I have discovered another aspect. If you closely participate in the implementation process of a task carried out by someone else—engaging in discussions about progress, problems, taking notes, etc.—you also gain detailed knowledge of how to implement it.

In conclusion, my initial assumption was not the minimal conclusion in terms of the level of detail required. The minimal level is having a good level of communication and involvement in the process.

How do I make a Docker container start automatically on system boot?

I have a Redis/Redis Stack container that I would like to start automatically at system boot. Since it is already running, I needed command

docker update --restart=always aa6daa0d965e

However, if it is starting for the first time, I use command

docker run --restart=always

There is also a third option: transform the container into a service and manage it with systemctl: https://stackoverflow.com/a/39493500/2806801.