Stories with Tag Process Management

• Show HN: Interactive systemd (a better way to work with systemd units)

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  Posted: 2025-01-18 16:22:03

  Verbose tl;dr

  isd is an interactive command-line tool designed to simplify working with systemd units. It provides a TUI (terminal user interface) that allows users to browse, filter, start, stop, restart, enable, disable, and edit unit files, as well as view their logs and status in real-time, all within an intuitive and interactive environment. This aims to offer a more user-friendly alternative to traditional command-line tools for managing systemd, streamlining common tasks and reducing the need to memorize complex commands.

  The Hacker News post titled "Show HN: Interactive systemd (a better way to work with systemd units)" introduces a new command-line tool called isd (Interactive Systemd) designed to simplify and streamline the management of systemd units. isd provides an interactive text-based user interface (TUI) built with Python and the curses library, offering a more intuitive and discoverable alternative to traditional command-line tools like systemctl.

  The core functionality of isd revolves around presenting a dynamically updating list of systemd units within a terminal window. Users can navigate this list using keyboard controls (arrow keys, PgUp/PgDown) and perform various actions on selected units directly within the interface. These actions include: starting, stopping, restarting, enabling, disabling, masking, and unmasking units. The status of each unit (active, inactive, failed, etc.) is clearly displayed in real-time, providing immediate feedback on executed commands.

  isd enhances the user experience by offering several features not readily available with standard systemctl usage. A built-in search functionality allows users to quickly filter the unit list by typing partial or full unit names. The interface also displays detailed information about a selected unit, including its description, loaded configuration file, and current status details. Additionally, isd includes a log viewer that streams the journal logs for a selected unit directly within the TUI, eliminating the need to switch between different terminal windows or commands to monitor unit activity.

  The project aims to lower the barrier to entry for systemd management, especially for users less familiar with the command-line interface or the complexities of systemctl. By providing a visual and interactive environment, isd simplifies the process of managing systemd units, making it easier to monitor, control, and troubleshoot services and other system components. The project is open-source and available on GitHub, encouraging community contributions and further development. The post highlights the key benefits of using isd, emphasizing its interactive nature, real-time updates, integrated log viewer, and simplified workflow compared to traditional methods. It positions isd as a valuable tool for both novice and experienced system administrators.

  • systemd
  • Linux
  • sysadmin
  • DevOps
  • command-line
  • cli
  • interactive
  • tui
  • terminal
  • system administration
  • service management
  • Process Management
  • utility
  • Open Source
  • Tool

  Summary of Comments ( 19 )
  https://news.ycombinator.com/item?id=42749402

  Verbose tl;dr

  Hacker News users generally praised the Interactive systemd (ISD) project for its intuitive and user-friendly approach to managing systemd units. Several commenters highlighted the benefits of its visual representation and the ease with which it allows users to start, stop, and restart services, especially compared to the command-line interface. Some expressed interest in specific features like log viewing and real-time status updates. A few users questioned the necessity of a TUI for systemd management, suggesting existing tools like systemctl are sufficient. Others raised concerns about potential security implications and the project's dependency on Python. Despite some reservations, the overall sentiment towards ISD was positive, with many acknowledging its potential as a valuable tool for both novice and experienced Linux users.

  The Hacker News post discussing the "Interactive systemd" project generated a moderate amount of discussion, mostly revolving around existing tools and alternative approaches to systemd management.

  Several commenters pointed out existing tools that offered similar functionality, such as systemctl status -l, which provides detailed status information for units. One user mentioned using journalctl -fu <unit> for following logs, suggesting the interactive systemd project might be over-engineered for simple use cases. This sentiment was echoed by another who found existing tools sufficient and preferred their terminal's copy-paste functionality.

  The discussion touched upon the perceived complexity of systemd itself. One commenter expressed their dislike for systemd, finding its structure unnecessarily complex and expressing a preference for simpler init systems like OpenRC and runit. Another user argued that while systemd is complex, this project doesn't address the underlying complexity; instead, it simply offers a different interface. They suggested that improving systemd's documentation might be a more effective approach.

  Some commenters appreciated the visual representation offered by the interactive systemd tool, particularly for exploring relationships between units. One user praised the tool's potential for educational purposes, allowing users to visualize the systemd structure and understand the dependencies between various services. Another found value in the tool for navigating complex systems and quickly grasping the overall state of different units.

  A few commenters focused on specific technical aspects. One inquired about the possibility of integrating the tool with other systemd management tools like Cockpit. Another raised the issue of handling large numbers of units and potential performance implications. The discussion also briefly touched on the use of Python and the psutil library, with one commenter mentioning an alternative Python library for systemd interaction.

  Finally, the original poster (OP) engaged with several comments, answering questions about the project's motivation, technical implementation, and future plans. They clarified that the tool is intended to complement existing tools, not replace them, and highlighted its unique features such as the visualization of unit dependencies and interactive exploration. The OP also acknowledged the feedback regarding existing alternatives and expressed interest in exploring integration with other tools.

• Why is my CPU usage always 100%?

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  Posted: 2025-01-09 21:15:33

  Verbose tl;dr

  The author's Chumby 8, a vintage internet appliance, consistently ran at 100% CPU usage due to a kernel bug affecting the way the CPU's clock frequency was handled. The original kernel expected a constant clock speed, but the Chumby's CPU dynamically scaled its frequency. This discrepancy caused the kernel's timekeeping functions to malfunction, leading to a busy loop that consumed all available CPU cycles. Upgrading to a newer kernel, compiled with the correct configuration for a variable clock speed, resolved the issue and brought CPU usage back to normal levels.

  This blog post, titled "Why is my CPU usage always 100%? (Upgrading my Chumby 8 kernel part 9)", details the author's ongoing journey to upgrade the Linux kernel on their Chumby 8, a now-discontinued internet appliance. A persistent issue of 100% CPU utilization plagues the device after the kernel upgrade, prompting a deep dive into diagnosing the root cause.

  Initially, the author suspects a runaway process is consuming all available CPU cycles. Using the top command, they identify the culprit as the kworker process, specifically a kernel thread dedicated to handling software interrupts. This discovery shifts the focus from a misbehaving user-space application to a problem within the kernel itself.

  The author's investigation then explores various potential sources of excessive software interrupts. They meticulously eliminate possibilities such as network interrupts by disconnecting the device from the network, and timer interrupts by analyzing their frequency and confirming they are within expected parameters.

  The post highlights the challenges of debugging kernel-level issues, especially on an embedded system with limited resources and debugging tools. The author leverages the available tools, including top, /proc/interrupts, and kernel debugging messages, to progressively narrow down the problem.

  Through a process of elimination and careful observation, the author eventually identifies the excessive software interrupts as stemming from the SD card driver. The continuous stream of interrupts from the SD card controller overwhelms the system, leading to the observed 100% CPU usage. While the exact reason for the SD card driver's behavior remains unclear at the end of the post, the author pinpoints the source of the problem and sets the stage for further investigation in future installments. The post concludes by emphasizing the iterative nature of debugging and the importance of systematically eliminating potential causes.

  • CPU Usage
  • High CPU Usage
  • Troubleshooting
  • performance
  • Chumby
  • Kernel
  • Embedded Systems
  • Linux
  • Operating System
  • optimization
  • System Resources
  • Process Management
  • Software Optimization
  • Linux Kernel
  • Kernel Debugging
  • Operating System Optimization

  Summary of Comments ( 74 )
  https://news.ycombinator.com/item?id=42649862

  Verbose tl;dr

  The Hacker News comments primarily focus on the surprising complexity and challenges involved in the author's quest to upgrade the kernel of a Chumby 8. Several commenters expressed admiration for the author's deep dive into the embedded system's inner workings, with some jokingly comparing it to a software archaeological expedition. There's also discussion about the prevalence of inefficient browser implementations on embedded devices, contributing to high CPU usage. Some suggest alternative approaches, like using a lightweight browser or a different operating system entirely. A few commenters shared their own experiences with similar embedded devices and the difficulties in optimizing their performance. The overall sentiment reflects appreciation for the author's detailed troubleshooting process and the interesting technical insights it provides.

  The Hacker News post discussing the blog post "Why is my CPU usage always 100%? Upgrading my Chumby 8 kernel (Part 9)" has several comments exploring various aspects of the situation and offering potential solutions.

  One commenter points out the inherent difficulty in debugging such embedded systems, highlighting the lack of sophisticated tools and the often obscure nature of the problems. They sympathize with the author's struggle, acknowledging the frustration that can arise when dealing with limited resources and cryptic error messages.

  Another commenter questions the author's decision to stick with the older kernel (2.6.32), suggesting that moving to a more modern kernel might be a more efficient approach in the long run. They acknowledge the author's stated reasons for remaining with the older kernel (familiarity and control) but argue that the benefits of a newer kernel, including potential performance improvements and bug fixes, might outweigh the effort involved in upgrading.

  A third commenter focuses on the specific issue of the kworker process consuming high CPU. They suggest investigating whether a driver is misbehaving or if some background process is stuck in a loop. They propose using tools like strace or perf to pinpoint the culprit and gain a better understanding of the kernel's behavior. This commenter also mentions the possibility of a hardware issue, although they consider it less likely.

  Further discussion revolves around the challenges of real-time systems and the potential impact of interrupt handling on CPU usage. One commenter suggests examining interrupt frequencies and considering the possibility of interrupt coalescing to reduce overhead.

  Finally, there's a brief exchange about the Chumby device itself, with one commenter expressing nostalgia for the device and another sharing their own experience with embedded systems development. This adds a touch of personal reflection to the technical discussion.

  Overall, the comments provide a valuable extension to the blog post, offering diverse perspectives on debugging embedded systems, troubleshooting high CPU usage, and the specific challenges posed by the Chumby 8 and its older kernel. The commenters offer practical suggestions and insights drawn from their own experiences, creating a collaborative problem-solving environment.