Posts

What is a Helm Subchart and How to Use It When you start using Helm to manage applications in Kubernetes, you’ll quickly discover that not everything should live in a single chart. Sometimes, an application depends on other components — like a database, cache, or monitoring tool. This is where subcharts come into play. What is a Subchart? A subchart is simply another Helm chart that lives inside the charts/ directory of your main chart. It’s a way to define dependencies. For example, your app may need Redis. Instead of reinventing the wheel, you include the Redis Helm chart as a subchart. ...

What is mbuffer and How It Can Be Useful When working with large data transfers in Linux — for example, copying databases, streaming backups, or piping data over the network — you might face performance bottlenecks. This is where mbuffer comes in. What is mbuffer? mbuffer (short for media buffer) is a tool that adds a high-performance buffer between a producer (like tar, dd, pg_dump) and a consumer (like ssh, gzip, disk). It works like a smart middleman: it temporarily stores data in memory and forwards it more smoothly. ...

What is Syncoid and How It Can Be Useful If you use ZFS on Linux or BSD, you might have datasets and snapshots that need to be replicated between servers. Syncoid is a tool that simplifies ZFS replication and backup. Why Syncoid? Automates snapshot replication — copies snapshots between datasets or servers. Incremental transfers — only changes are sent over the network, saving bandwidth. Easy CLI usage — no need to write complex ZFS send/receive scripts. Supports remote hosts — replication over SSH is built-in. Example: Basic Syncoid Usage Assume you have a source dataset tank/data and want to replicate it to backup/data on a remote server: ...

Optimizing etcd on Slow Disks in Kubernetes In Kubernetes, etcd is the central database that stores the entire cluster state. If etcd runs on slow disks, you might notice performance issues: API requests slow down, pods take longer to schedule, and sometimes the cluster feels “laggy.” Why etcd Struggles on Slow Disks etcd is very I/O-intensive. Each write goes to disk to guarantee consistency. On spinning HDDs or cheap cloud disks with poor IOPS, etcd can quickly become a bottleneck. ...

What is CORS (Cross-Origin Resource Sharing) If you’ve ever worked with APIs in the browser, you probably saw this error: Access to fetch at ‘https://api.example.com/data from origin ‘http://localhost:3000 has been blocked by CORS policy This happens because of CORS — Cross-Origin Resource Sharing. Why CORS Exists Browsers follow the same-origin policy for security. It means that scripts loaded from one origin (domain, protocol, port) cannot freely access resources from another. Otherwise, any website could secretly read your banking data if you’re logged in. ...