Resolving commands 'Killed' on GCP f1-micro Compute Engine instances

Resolving commands 'Killed' on GCP f1-micro Compute Engine instances

When I want to perform a quick task, I generally spin up a Google GCP Compute Engine instance as they’re cheap. However, they have limited resources, particularly memory. When refreshing the package repositories, it’s quite easy to encounter an Out-of-Memory (OOM) situation which results in the command - yum or dnf - is ‘killed’. For example:

$ sudo dnf update 
CentOS Stream 8 - AppStream                                                                                                  8.3 MB/s |  18 MB     00:02    
CentOS Stream 8 - BaseOS                                                                                                      13 MB/s |  16 MB     00:01    
CentOS Stream 8 - Extras                                                                                                      69 kB/s |  16 kB     00:00    
Google Compute Engine                                                                                                         20 kB/s | 9.4 kB     00:00    
Google Cloud SDK                                                                                                              24 MB/s |  43 MB     00:01    
Killed

dmesg has a lot of information about the situation, but the key line to confirm dnf caused the OOM event, is:

[ 1156.249100] Out of memory: Killed process 1538 (dnf) total-vm:638020kB, anon-rss:290432kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtables:1244kB oom_score_adj:0

Many of the OS images provided by GCP and other cloud providers, often do not provide a swap device which is fine for the larger instances but may be required on the smaller memory instances.

To resolve the situation, create a swap device for the instance. The following adds 1GB which is typically enough for the dnf and yum commands.

sudo fallocate -l 1G /swapfile
sudo mkswap /swapfile
sudo chmod 0600 /swapfile
sudo swapon /swapfile

Note: The above is not permanent, so you’ll want to add an entry to the /etc/fstab to ensure the swap device is added on each boot, eg:

/swapfile none                    swap    defaults        0 0

Programming Persistent Memory: A Comprehensive Guide for Developers Book

Programming Persistent Memory: A Comprehensive Guide for Developers Book

After many months of hard work by everyone involved, I’m very pleased to announce that the book “Programming Persistent Memory: A Comprehensive Guide for Developers” is now available for download in digital PDF & ePUB formats from https://pmem.io/book , and Kindle & paperback through Amazon .

Beginner and experienced programmers will use this comprehensive guide to persistent memory programming. You will understand how persistent memory brings together several new software/hardware requirements, and offers great promise for better performance and faster application startup times―a huge leap forward in byte-addressable capacity compared with current DRAM offerings.
This revolutionary new technology gives applications significant performance and capacity improvements over existing technologies. It requires a new way of thinking and developing, which makes this highly disruptive to the IT/computing industry. The full spectrum of industry sectors that will benefit from this technology include, but are not limited to, in-memory and traditional databases, AI, analytics, HPC, virtualization, and big data.   
Programming Persistent Memory describes the technology and why it is exciting the industry. It covers the operating system and hardware requirements as well as how to create development environments using emulated or real persistent memory hardware. The book explains fundamental concepts; provides an introduction to persistent memory programming APIs for C, C++, JavaScript, and other languages; discusses RMDA with persistent memory; reviews security features; and presents many examples. Source code and examples that you can run on your own systems are included.
What You’ll Learn
- Understand what persistent memory is, what it does, and the value it brings to the industry
- Become familiar with the operating system and hardware requirements to use persistent memory
- Know the fundamentals of persistent memory programming: why it is different from current programming methods, and what developers need to keep in mind when programming for persistence
- Look at persistent memory application development by example using the Persistent Memory Development Kit (PMDK)
- Design and optimize data structures for persistent memory
- Study how real-world applications are modified to leverage persistent memory
- Utilize the tools available for persistent memory programming, application performance profiling, and debugging
Who This Book Is For
C, C++, Java, and Python developers, but will also be useful to software, cloud, and hardware architects across a broad spectrum of sectors, including cloud service providers, independent software vendors, high performance compute, artificial intelligence, data analytics, big data, etc. 

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How To Verify Linux Kernel Support for Persistent Memory

How To Verify Linux Kernel Support for Persistent Memory

Linux Kernel support for persistent memory was first delivered in version 4.0 of the mainline kernel, however, it was not enabled by default until version 4.2.

If you use a Linux distribution that uses kernel 4.2 or later, or the distro backports features in to an older kernel, you will almost certainly have persistent memory support enabled by default. It is still worth verifying what features are enabled and disabled as this may vary by distro and release version for the very latest persistent memory features.

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I Turned Myself Into an Action Figure

I Turned Myself Into an Action Figure

Part of being in tech, especially in emerging memory technology, is constantly switching between the serious and the surreal. One day you’re in kernel debug mode, the next you’re explaining complex system architectures on a whiteboard, and then suddenly you’re jumping on the latest craze such as making yourself into an action figure.

It’s fun. It’s human. And honestly? It’s a reminder not to take yourself too seriously. (Even if your job title suggests differently)

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