Red Hat Enterprise Linux

Making the Operation of Code More Transparent and Obvious

You can study source code and manually instrument functions as described in the “Use the dynamic tracing tools, Luke” blog article, but why not make it easier to find key points in the software by adding user-space markers to the application code? User-space markers have been available in Linux for quite some time (since 2009). The inactive user-space markers do not significantly slow down the code. Having them available allows you to get a more accurate picture of what the software is doing internally when unexpected issues occur. The diagnostic instrumentation can be more portable with the user-space markers, because the instrumentation does not need to rely on instrumenting particular function names or lines numbers in source code. The naming of the instrumentation points can also make clearer what event is associated with a particular instrumentation point.

For example, Ruby MRI on Red Hat Enterprise Linux 7 has a number of different instrumentation points made available as a SystemTap tapset. If SystemTap is installed on the system, as described by What is SystemTap and how to use it?, the installed Ruby MRI instrumentation points can be listed with the stap -L” command shown below. These events show the start and end of various operations in the Ruby runtime, such as the start and end of garbage collection (GC) marking and sweeping.

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“Use the dynamic tracing tools, Luke”

A common refrain for tracking down issues on computer systems running open source software is “Use the source, Luke.” Reviewing the source code can be helpful in understanding how the code works, but the static view may not give you a complete picture of how things work (or are broken) in the code. The paths taken through code are heavily data dependent. Without knowledge about specific values at key locations in code, you can easily miss what is happening. Dynamic instrumentation tools, such as SystemTap, that trace and instrument the software can help provide a more complete understanding of what the code is actually doing

I have wanted to better understand how the Ruby interpreter works. This is an opportunity to use SystemTap to investigate Ruby MRI internals on Red Hat Enterprise Linux 7. The article What is SystemTap and how to use it? has more information about installing SystemTap. The x86_64 RHEL 7 machine has ruby-2.0.0648-33.el7_4.x86_64.rpm installed, so the matching debuginfo RPM is installed to provide SystemTap with information about function parameters and to provide me with human-readable source code. The debuginfo RPM is installed by running the following command as root:

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Expanding architectural choices to better arm Red Hat Enterprise Linux developers

Red Hat Enterprise Linux continues to deliver the best possible experience for enterprise system administrators and developers, as well as provide a solid foundation for moving workloads into both public and private clouds. One of the ways to enable such ubiquity is Red Hat’s multi-architecture initiative, which focuses on bringing Red Hat’s software portfolio to different hardware architectures.

Last week, Red Hat Enterprise Linux 7.5 went live. It brought forward several improvements relevant to developers and system administrators such as advanced GUI system management via the Cockpit console, which should help new Linux administrators, developers, and Windows users to perform expert tasks without having to get into the command line.

This release also marks a new milestone for Red Hat Enterprise Linux: all supported architectures are now simultaneously enabled. The list of supported architectures includes x86_64, PowerPC Big Endian and Little Endian, s390x, and the more recently introduced 64-bit Arm and IBM POWER9 architectures.

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Deallocate an Azure VM Using the Azure CLI on RHEL

If you’re running Red Hat Enterprise Linux server on Microsoft Azure, you may want to shut down and deallocate the VM using commands inside of the VM itself for automation or just for convenience. On Azure, if you shut down the VM by using shutdown -h or another OS command, it will stop but not deallocate it.  The stopped VM is still using resources and will continue to incur compute charges. To avoid that, this article shows how a VM can shut itself down and deallocate its resources using the Azure CLI 2.0.

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Red Hat scripting languages for beta: adds Ruby 2.5, Perl 5.26; updates PHP 7.1.8

Twice a year, Red Hat distributes new versions of compiler toolsets, scripting languages, open source databases, and/or web tools, etc. so that application developers will have access to the latest, stable versions. These Red Hat supported offerings are packaged as Red Hat Software Collections (scripting languages, open source databases, web tools, etc.), Red Hat Developer Toolset (GCC), and the recently added compiler toolsets Clang/LLVM, Go, and Rust. All are yum installable, and are included in most Red Hat Enterprise Linux subscriptions and all Red Hat Enterprise Linux Developer Subscriptions. Most Red Hat Software Collections and Red Hat Developer Toolset components are also available as Linux container images for hybrid cloud development across Red Hat Enterprise Linux, Red Hat OpenShift Container Platform, etc.

Red Hat Software Collections 3.1 beta brings the following new/updated scripting languages:

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Red Hat adds/updates web tools for beta: HAProxy 1.8, Varnish 5.0, Apache httpd 2.4

Twice a year, Red Hat distributes new versions of compiler toolsets, scripting languages, open source databases, and/or web tools, etc. so that application developers will have access to the latest, stable versions. These Red Hat supported offerings are packaged as Red Hat Software Collections (scripting languages, open source databases, web tools, etc.), Red Hat Developer Toolset (GCC), and the recently added compiler toolsets Clang/LLVM, Go, and Rust. All are yum installable, and are included in most Red Hat Enterprise Linux subscriptions and all Red Hat Enterprise Linux Developer Subscriptions. Most Red Hat Software Collections and Red Hat Developer Toolset components are also available as Linux container images for hybrid cloud development across Red Hat Enterprise Linux, Red Hat OpenShift Container Platform, etc.

With the new Red Hat Software Collections 3.1 beta release, these web tools are now available:

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New Red Hat compilers toolsets in beta: Clang and LLVM, GCC, Go, Rust

Twice a year, Red Hat distributes new versions of compiler toolsets, scripting languages, open source databases, and/or web tools, etc. so that application developers will have access to the latest, stable versions. These Red Hat supported offerings are packaged as Red Hat Software Collections (scripting languages, open source databases, web tools, etc.), Red Hat Developer Toolset (GCC), and the recently added compiler toolsets Clang/LLVM, Go, and Rust. All are yum installable, and are included in most Red Hat Enterprise Linux subscriptions and all Red Hat Enterprise Linux Developer Subscriptions. Most Red Hat Software Collections and Red Hat Developer Toolset components are also available as Linux container images for hybrid cloud development across Red Hat Enterprise Linux, Red Hat OpenShift Container Platform, etc.

The new/updated compiler toolsets are:

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Red Hat open source databases in beta: Adds PostgreSQL 10, MongoDB 3.6; updates MySQL 5.7

Twice a year, Red Hat distributes new versions of compiler toolsets, scripting languages, open source databases, and/or web tools, etc. so that application developers will have access to the latest, stable versions. These Red Hat supported offerings are packaged as Red Hat Software Collections (scripting languages, open source databases, web tools, etc.), Red Hat Developer Toolset (GCC), and the recently added compiler toolsets Clang/LLVM, Go, and Rust. All are yum installable, and are included in most Red Hat Enterprise Linux subscriptions and all Red Hat Enterprise Linux Developer Subscriptions. Most Red Hat Software Collections and Red Hat Developer Toolset components are also available as Linux container images for hybrid cloud development across Red Hat Enterprise Linux, Red Hat OpenShift Container Platform, etc.

Red Hat Software Collections 3.1 beta brings the following new/updated open source databases:

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Analyzing Changes to the Binary Interface Between the Linux Kernel and its Modules

This article is for people interested in long-term Linux kernel maintenance. It introduces you to tools that can help keep the binary interfaces between the kernel and its loadable modules stable during the entire lifetime of a supposedly stable kernel, while the code is modified. As these tools are essentially analysis tools, they can be used not only by kernel developers, but also by quality assurance engineers and advanced kernel users (system programmers).

Upstream in-tree kernel modules: the ideal situation

In the canonical development model of the Linux kernel, the source code of all dynamically loaded modules is hosted alongside the source code of the core kernel. In this model, whenever the core kernel changes the interface it exposes to its modules, the compilers detects that the interface changed, making it easy to adjust the code of the modules accordingly.

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