Securing a Zookeeper ensemble

Even in secured networks, it’s a good idea to use some of the security features available in Zookeeper. In this post we’ll look at two security mechanisms: mutual TLS (mTLS) and SASL authentication. We’ll set up these security features on the server-server communication (leader election protocols) and client-server communication (Kafta to Zookeeper).

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Building a Zookeeper ensemble

Some notes on setting up and configuring a Zookeeper ensemble. Many guides use some shortcuts to setting up the ensemble such as running multiple Zookeeper instances on a single machine or running them in Docker. Both require some workarounds to make it work. As a better example, this guide runs three Zookeeper instances across three different VMs.

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Microsoft Bot Framework Part 3: Connect to channels

In the first two parts we built a bot using the Microsoft Bot Framework SDK and registered it in Azure. In this third and final part we’ll consume the bot using three of the available Bot Framework Channels: A simple chat component on a web page, SMS text and a fully custom Node.js application.

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Microsoft Bot Framework Part 2: Build a bot with Bot Framework SDK

In the first part, we created an Azure Bot registration and connected to a demo bot application. In this part we’ll swap out the demo bot for one we’ve built using the Microsoft Bot Framework SDK.

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Microsoft Bot Framework Part 1: Create an Azure Bot Resource

In this part, I’ll register and configure a bot with Microsoft Azure Bot Service. It might seem odd to start here rather than going straight into the application code. However, getting this step out of the way gives us something simple to play with that works end to end.

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Exception handling in ScheduledExecutorService

Java’s ScheduledExecutorService allows you to schedule Runnable tasks without having to worry too much about creating Threads. But how do we handle this exception? We have a few options.

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The epoch was an hour late

On the moment that is represented as zero in Unix, C, Java and so many other systems, Big Ben did not strike twelve. At midnight on the 1st January 1970, Big Ben struck one.

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Execute Around idiom in Java

The Execute Around idiom is a pattern that allows you to wrap an action with some standard setup / tear down steps. Examples might include: Execute within a lock: acquire the lock, do the action, release the lock Resource handling: acquire the resource, do the action, close the resource Execute as a user: switch to read more »

Reverse order a Stream in Java

How do you reverse order a Stream in Java? There’s no obvious Stream.reverse() method. Is this an oversight in the API? Is there a workaround?

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Private DNS for Native Windows Docker Container

Docker Windows containers have a number of shortcomings, particularly around networking. One serious showstopper is that it doesn’t use the DNS of its host server.

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