MikroTik – RouterOSv7 first look – feedback on routing filters

Overview

Routing filters have been a hot topic lately in the world of RouterOSv7. The first implementation of routing filters in ROSv7 was difficult to work with and documented in the two articles below:

MikroTik – RouterOSv7 first look – Dynamic routing with IPv6 and OSPFv3/BGP

MikroTik RouterOS – v7.0.3 stable (chateau) and status of general release


MikroTik then made some changes and opened up discussion to get feedback. I did a lot of work and testing using ROS 7.1beta7 which never made it to public release and was close to publishing the results when 7.1rc1 came out so this post will use that version.

https://forum.mikrotik.com/viewtopic.php?f=1&t=175201#p867750


RouterOSv7.1rc1 syntax example

Here is an example of the latest syntax in ROSv7.1rc1

CLI

### MikroTik RouterOS 7.1rc1 ###

/routing filter rule
add chain=dead.beef.101 rule="if (dst==200:dead:beef:101::/64) {accept}"
add chain=dead.beef.102 rule="if (dst==200:dead:beef:102::/64) {accept}"
add chain=dead.beef.agg rule="if (dst in 200:dead:beef::/48) {accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.101) {set bgp-local-pref 300; accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.102) {accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.agg && dst-len<128) {set bgp-local-pref 150; accept}"

Winbox


And the corresponding routes received Continue reading

Introducing logs from the dashboard for Cloudflare Workers

Introducing logs from the dashboard for Cloudflare Workers
Introducing logs from the dashboard for Cloudflare Workers

If you’re writing code: what can go wrong, will go wrong.

Many developers know the feeling: “It worked in the local testing suite, it worked in our staging environment, but… it’s broken in production?” Testing can reduce mistakes and debugging can help find them, but logs give us the tools to understand and improve what we are creating.

if (this === undefined) {
  console.log("there’s no way… right?") // Narrator: there was.
}

While logging can help you understand when the seemingly impossible is actually possible, it’s something that no developer really wants to set up or maintain on their own. That’s why we’re excited to launch a new addition to the Cloudflare Workers platform: logs and exceptions from the dashboard.

Starting today, you can view and filter the console.log output and exceptions from a Worker… at no additional cost with no configuration needed!

View logs, just a click away

When you view a Worker in the dashboard, you’ll now see a “Logs” tab which you can click on to view a detailed stream of logs and exceptions. Here’s what it looks like in action:

Each log entry contains an event with a list of logs, exceptions, Continue reading

The Next Phase of Cloud-Grade Routing

The Next Phase of Cloud-Grade Routing

In the past decade, the emergence of cloud networks has blurred the line between switching and routing versus traditional routers. Today the industry is at an inflection point, where the adoption of cloud principles for routing intersects the rapidly expanding capabilities of the merchant silicon feature set and scale, creating a disruption of legacy routing architectures.

How to choose the best NVMe storage array

Storage will never be as fast as system memory--that’s just the nature of system architecture. But thanks to NVMe (nonvolatile memory express), SSDs can deliver such blazingly fast performance, the penalty of “going to disk” tends to be miniscule.NVMe encompasses a family of specifications for how software talks to storage. It works over a number of transport methods, including PCI Express, RDMA, and TCP. Storage arrays that support the NVMe standard are the sports cars of storage, exposing super-fast storage media more directly and efficiently than any other mainstream method allows.To read this article in full, please click here

Choosing and changing your Linux shell

There are quite a few shells on Linux system and more that can be easily added. This post examines some of the more popular shells, how they differ and the files that contribute to their configuration.The default shell on most Linux systems is bash. Unless you make an effort, any user accounts added to the system will be assigned bash as their login shell. Bash has been around since 1989 and was meant to replace the Bourne shell (sh). In fact, if you take a look at /bin/sh, you'll probably find that it's nothing more than a symbolic link to /bin/bash.$ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 25 2021 /bin/sh -> bash Summarizing your command-line usage on Linux   Popular Shells Some of the best and most popular shells include:To read this article in full, please click here

How to choose the best NVMe storage array

Storage will never be as fast as system memory--that’s just the nature of system architecture. But thanks to NVMe (nonvolatile memory express), SSDs can deliver such blazingly fast performance, the penalty of “going to disk” tends to be miniscule.NVMe encompasses a family of specifications for how software talks to storage. It works over a number of transport methods, including PCI Express, RDMA, and TCP. Storage arrays that support the NVMe standard are the sports cars of storage, exposing super-fast storage media more directly and efficiently than any other mainstream method allows.To read this article in full, please click here

Choosing and changing your Linux shell

There are quite a few shells on Linux system and more that can be easily added. This post examines some of the more popular shells, how they differ and the files that contribute to their configuration.The default shell on most Linux systems is bash. Unless you make an effort, any user accounts added to the system will be assigned bash as their login shell. Bash has been around since 1989 and was meant to replace the Bourne shell (sh). In fact, if you take a look at /bin/sh, you'll probably find that it's nothing more than a symbolic link to /bin/bash.$ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 25 2021 /bin/sh -> bash Summarizing your command-line usage on Linux   Popular Shells Some of the best and most popular shells include:To read this article in full, please click here

eBPF: When (and when not) to use it

Extended Berkeley Packet Filter (eBPF) is a relatively new feature for Linux kernels that has many DevOps, SREs, and engineers excited. But is it a one-stop shop solution for all of your Linux kernel needs? Let’s take a look at what eBPF does well, and how it stacks up against standard Linux iptables.

 

What is eBPF?

eBPF is a feature available in Linux kernels that allows you to run a virtual machine inside the kernel. This virtual machine allows you to safely load programs into the kernel, in order to customize its operation. Why is this important?

In the past, making changes to the kernel was difficult: there were APIs you could call to get data, but you couldn’t influence what was inside the kernel or execute code. Instead, you had to submit a patch to the Linux community and wait for it to be approved. With eBPF, you can load a program into the kernel and instruct the kernel to execute your program if, for example, a certain packet is seen or another event occurs.

With eBPF, the kernel and its behavior become highly customizable, instead of being fixed. This can be extremely beneficial, when used Continue reading

ThinkPad X1 Carbon (Gen 7): 2 years later

Two years ago, I replaced my ThinkPad X1 Carbon 2014 with the latest generation. The new configuration embeds an Intel Core i7-8565U, 16 Gib of RAM, a 1 Tib NVMe disk, and a WQHD display (2560×1440). I did not ask for a WWAN card. I think it is easier and more reliable to use the wifi hotspot feature of a phone instead: no unreliable firmware and unsupported drivers.1 Here is my opinion on this model.

ThinkPad X1 Carbon 7th Gen with the lid closed
ThinkPad X1 Carbon with its lid closed

While the second generation got a very odd keyboard, this one got a classic one with a full row of function keys. I don’t know if my model was defective, but the keyboard skips one keypress from time to time. I have got used to it, but the space key still has a hard time registering when hitting it with my right thumb. The travel course is also shorter and it is less comfortable to type on it than it was on the 2014 version. The trackpoint2 works well. The physical buttons are a welcome addition. I am only using the trackpad for scrolling with the two-finger gesture.

Keyboard of the X1 Carbon 7th Gen
Keyboard with an ANSI QWERTY layout (aka English EU for Continue reading

Using the AWS CLI to Tag Groups of AWS Resources

To conduct some testing, I recently needed to spin up a group of Kubernetes clusters on AWS. Generally speaking, my “weapon of choice” for something like this is Cluster API (CAPI) with the AWS provider. Normally this would be enormously simple. In this particular case—for reasons that I won’t bother going into here—I needed to spin up all these clusters in a single VPC. This presents a problem for the Cluster API Provider for AWS (CAPA), as it currently doesn’t add some required tags to existing AWS infrastructure (see this issue). The fix is to add the tags manually, so in this post I’ll share how I used the AWS CLI to add the necessary tags.

Without the necessary tags, the AWS cloud provider—which is responsible for the integration that creates Elastic Load Balancers (ELBs) in response to the creation of a Service of type LoadBalancer, for example— won’t work properly. Specifically, the following tags are needed:

kubernetes.io/cluster/<cluster-name>
kubernetes.io/role/elb
kubernetes.io/role/internal-elb

The latter two tags are mutually exclusive: the former should be assigned to public subnets to tell the AWS cloud provider where to place public-facing ELBs, while the latter is assigned to private subnets Continue reading

It always takes longer than you think

Everyone is aware that it always takes longer to find a problem in a network than it should. Moving through the troubleshooting process often feels like swimming in molasses—you’re pulling hard, and progress is being made, but never fast enough or far enough to get the application back up and running before that crucial deadline. The “swimming in molasses effect” doesn’t end when the problem is found out, either—repairing the problem requires juggling a thousand variables, most of which are unknown, combined with the wit and sagacity of a soothsayer to work with vendors, code releases, and unintended consequences.

It’s enough to make a network engineer want to find a mountain top and assume an all-knowing pose—even if they don’t know anything at all.
The problem of taking longer, though, applies in every area of computer networking. It takes too long for the packet to get there, it takes to long for the routing protocol to converge, it takes too long to support a new application or server. It takes so long to create and validate a network design change that the hardware, software and processes created are obsolete before they are used.

Why does it always take too long? Continue reading

Intel shifts to multiarchitecture model

There was a time when Intel was all-x86, all the time, everywhere.Not anymore.Last week Intel held its annual Architecture Day with previews of multiple major upcoming architectures beyond x86. For once, it’s not hyperbole when they say these are some of the “biggest shifts in a generation.”CEO Gelsinger shakes up Intel And it’s not just architectures or just more and faster cores, it’s new designs, whole new ways of doing things. Instead of just packing more cores onto a smaller die, Intel is switching to a new hybrid architecture that adds low-energy-draw cores, similar to what some ARM chip makers have been doing for years on mobile devices.To read this article in full, please click here

Intel shifts to multiarchitecture model

There was a time when Intel was all-x86, all the time, everywhere.Not anymore.Last week Intel held its annual Architecture Day with previews of multiple major upcoming architectures beyond x86. For once, it’s not hyperbole when they say these are some of the “biggest shifts in a generation.”CEO Gelsinger shakes up Intel And it’s not just architectures or just more and faster cores, it’s new designs, whole new ways of doing things. Instead of just packing more cores onto a smaller die, Intel is switching to a new hybrid architecture that adds low-energy-draw cores, similar to what some ARM chip makers have been doing for years on mobile devices.To read this article in full, please click here

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