What’s New In Red Hat Ansible Tower 3.6

As part of the release of Red Hat Ansible Automation Platform, we’re happy to announce the release of Red Hat Ansible Tower 3.6. Ansible Tower is the scalable execution framework of the Ansible Automation Platform, providing an API around automation that you can use to scale automation across your enterprise and integrate automation into your tools and processes.

Workflow Pause and Approvals

Not all automation processes can proceed entirely without human input. In Ansible Tower 3.6, we’ve added pause and approval to Ansible Tower workflows to help enable more flexible automation. At any step in a workflow you can pause and wait for an approval from an administrator, or any other you delegate approval permissions to. Need to verify that your deployment was fully successful before updating the external DNS entries? Need to ensure that your developers won’t spin up 300 extra cloud servers when provisioning new dev environments? Now you can do that, integrated directly in Ansible Tower workflows.

Customizable Notifications

Notifications were introduced in Ansible Tower 3.0, allowing the status of any job to be reported out via email, Slack, IRC, and more. In Ansible Tower 3.6, we’ve made the content Continue reading

Best Analysis Finalist – Cisco IT Blog Awards for 2019

This blog was selected as a finalist in Cisco BLOG Awards in the Best Analysis category, the category for resources that provide insightful discussions and help for networking architects around the world. Fancy right? Do you agree? Go and vote, it’s the second one on the list ? https://www.ciscofeedback.vovici.com/se/705E3ECD18791A68

The post Best Analysis Finalist – Cisco IT Blog Awards for 2019 appeared first on How Does Internet Work.

Upcoming Workshops: NSX, ACI, VXLAN, EVPN, DCI and More

I’m running two workshops in Zurich in the next 10 days:

• Comparing VMware NSX and Cisco ACI (and how EVPN and VXLAN fit into the big picture) on Thursday, November 28th;
• Explaining how you could use VXLAN with EVPN to build infrastructure for active-active data centers on Tuesday, December 3rd.

I published the slide deck for the NSX versus ACI workshop a few days ago (and you can already download it if you have a paid ipSpace.net subscription) and it’s full of new goodness like ACI vPod, multi-pod ACI, multi-site ACI, ACI-on-AWS, and multi-site NSX-V and NSX-T.

Mergeable replicated data types – Part I

Mergeable replicated data types Kaki et al., OOPSLA’19

This paper was published at OOPSLA, but perhaps it’s amongst the distributed systems community that I expect there to be the greatest interest. Mergeable Replicated Data Types (MRDTs) are in the same spirit as CRDTs but with the very interesting property that they compose. Furthermore, a principled approach for deriving MRDTs is provided, allowing a wide range of data-types to be lifted to their mergeable, replicated counterparts with very little effort on the part of the programmer. The paper sets the discussion in the context of geo-replicated distributed systems, but of course the same mechanisms could be equally useful in the context of local-first applications.

There’s a lot of material in this paper’s 29 pages, and to make sure I have the space to properly understand the ideas (the process of summary writing is a critical part of that for me), I’m going to spread my coverage over two posts.

We’ll begin by looking at the context and the high-level idea behind MRDTs, then we’ll investigate how merge specifications can be derived and composed, and how merge implementations can be derived too. Finally we’ll touch on the implementation of MRDTs in Continue reading

8 ways to prepare your data center for AI’s power draw

As artificial intelligence takes off in enterprise settings, so will data center power usage. AI is many things, but power efficient is not one of them.For data centers running typical enterprise applications, the average power consumption for a rack is around 7 kW. Yet it’s common for AI applications to use more than 30 kW per rack, according to data center organization AFCOM. That’s because AI requires much higher processor utilization, and the processors – especially GPUs – are power hungry. Nvidia GPUs, for example, may run several orders of magnitude faster than a CPU, but they also consume twice as much power per chip. Complicating the issue is that many data centers are already power constrained.To read this article in full, please click here

8 ways to prepare your data center for AI’s power draw

As artificial intelligence takes off in enterprise settings, so will data center power usage. AI is many things, but power efficient is not one of them.For data centers running typical enterprise applications, the average power consumption for a rack is around 7 kW. Yet it’s common for AI applications to use more than 30 kW per rack, according to data center organization AFCOM. That’s because AI requires much higher processor utilization, and the processors – especially GPUs – are power hungry. Nvidia GPUs, for example, may run several orders of magnitude faster than a CPU, but they also consume twice as much power per chip. Complicating the issue is that many data centers are already power constrained.To read this article in full, please click here

The many faces of awk

If you only use awk when you need to select specific fields from lines of text, you might be missing out on a lot of other services that the command can provide. In this post, we'll look at this simple use along with many other things that awk can do for you with enough examples to show you that the command is a lot more flexible than you might have imagined.Plucking out columns of data The easiest and most commonly used service that awk provides is selecting specific fields from files or from data that is piped to it. With the default of using white space as a field separator, this is very simple:To read this article in full, please click here

Worth Reading: Early History of Usenet

Steve Bellovin wrote a great series of articles describing the early history of Usenet. The most interesting part in the “security and authentication” part was probably this gem:

That left us with no good choices. The infrastructure for a cryptographic solution was lacking. The uux command rendered illusory any attempts at security via the Usenet programs themselves. We chose to do nothing. That is, we did not implement fake security that would give people the illusion of protection but not the reality.

A lot of other early implementers chose the same route, resulting in SMTP, BGP… which wouldn’t be a problem if someone kept track of that and implemented security a few years later. Unfortunately we considered those problems solved and moved on to chase other squirrels. We’re still paying the interest on that technical debt.

CCDE Study Guide

Go Notes: Structs

Go Notes: Structs

Signals, Go & Immutable Infrastructure

From the days of old, setting fire to a large torch would signal to a neighbouring town something was going on. On the Great Wall in China, reports of signals reaching some 470 miles can be read on Wikipedia! Back to the future and modern day times, signals are transmitted and received as part of every application we touch. Signals underpin a system’s communications, irrelevant of what that system is. Software gives off many signals of a wide variety in normal operations and through signal correlation, we can yield useful events. Signals can also be used to achieve an outcome in a remote system as well as direct application API calls.

Being a fan of systems that have a natural synergy to them, I also look for ways to tie application functionality into natural system interactions.

For this post, I want to talk about the separation of concerns between an application’s functionality via it’s primary operational interface, likely an API of some sort, versus the application’s operational configuration, which allows it start on the correct TCP/IP port and consume the correct credential information.

Why not just get the application to refresh its configuration through the operational interface? The best way Continue reading

Worth Reading: Going Back to Being an Engineer

Another great advice from Charity Majors: does it make sense to go back to being an engineer after being a manager for a few years?

Personal note: finding a great replacement for my CTO role was probably the best professional decision I ever made ;)

Asynchronous Zsh prompt with Git status

Zsh ships vcs_info, a function fetching information about the VCS state for the current directory and populating a variable that can be used in a shell prompt. It supports several VCS, including Git and SVN. Here is an example of configuration:

autoload -Uz vcs_info
zstyle ':vcs_info:*' enable git

() {
    local formats="${PRCH[branch]} %b%c%u"
    local actionformats="${formats}%{${fg[default]}%} ${PRCH[sep]} %{${fg[green]}%}%a"
    zstyle ':vcs_info:*:*' formats           $formats
    zstyle ':vcs_info:*:*' actionformats     $actionformats
    zstyle ':vcs_info:*:*' stagedstr         "%{${fg[green]}%}${PRCH[circle]}"
    zstyle ':vcs_info:*:*' unstagedstr       "%{${fg[yellow]}%}${PRCH[circle]}"
    zstyle ':vcs_info:*:*' check-for-changes true
}

add-zsh-hook precmd vcs_info

You can use ${vcs_info_msg_0_} in your prompt to display the current branch, the presence of staged and unstaged changes, as well as the ongoing action.¹ Have a look at the documentation for more details.

On large repositories, some information are expensive to fetch. While vcs_info queries Git, interactions with Zsh are stuck. A possible solution is to execute vcs_info asynchronously with zsh-async.

Continue reading

Operators Dish on Edge Computing Strategies at MEF 2019

TCP MD5

TCP_MD5 (RFC 2385) is something that doesn’t come up often. There’s a couple of reasons for that, good and bad.

I used it with tlssh, but back then (2010) it was not practical due to the limitations in the API on Linux and OpenBSD.

This is an updated post, written after I discovered TCP_MD5SIG_EXT.

What it is

In short it’s a TCP option that adds an MD5-based signature to every TCP packet. It signs the source and destination IP addresses, ports, and the payload. That way the data is both authenticated and integrity protected.

When an endpoint enables TCP MD5, all unsigned packets (including SYN packets) are silently dropped. For a signed connection it’s not even possible for an eavesdropper to reset the connection, since the RST would need to be signed.

Because it’s on a TCP level instead of part of the protocol on top of TCP, it’s the only thing that can protect a TCP connection against RST attacks.

It’s used by the BGP protocol to set a password on the connection, instead of sending the password in the handshake. If the password doesn’t match the TCP connection doesn’t even establish.

But outside of BGP it’s essentially Continue reading

Talking System Architecture With AMD CTO Mark Papermaster

It is funny to think that in a certain light, AMD has Big Blue to thank for its resurgence in the datacenter. …

Talking System Architecture With AMD CTO Mark Papermaster was written by Timothy Prickett Morgan at The Next Platform.

BiB083 – Forescout – Visibility For Segmentation

BiB083 – Forescout – Visibility For Segmentation

I'm talking about Forescout after receiving a briefing during Tech Field Day 20.

The post BiB083 – Forescout – Visibility For Segmentation appeared first on Packet Pushers.

Technology Short Take 120

Welcome to Technology Short Take #120! Wow…hard to believe it’s been almost two months since the last Tech Short Take. Sorry about that! Hopefully something I share here in this Tech Short Take is useful or helpful to readers. On to the content!

Networking

• In the event you are seeking more information on NAT hole punching, here you go. You’re welcome. (I found this link in the serverless mullet architectures post, see the “Operating Systems/Applications” section below.)
• Mohamad Alhussein shares how to filter the transit subnets from being redistributed from NSX-T to upstream physical routers (by transit subnets Alhussein is referring to the NSX-managed subnets used to connect logical routers together).
• Ahmet Alp Balkan shows how to use mitmproxy to inspect kubectl traffic. I’m now inspired to go do this myself and see what knowledge I can gain.
• Corey Quinn proclaims “BGP is a hot mess”; Ivan Pepelnjak lays out some facts.

Servers/Hardware

I don’t have anything to share this time around, but I’ll stay alert for content to include future Tech Short Takes.

Security

• This basic introduction of firewalld as found in CentOS 8 may prove useful to some readers. I’ve been messing around with firewalld ever since Continue reading