docker-enterprise

How Pods access Kubernetes DNS in Docker EE, part one

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Service discovery is one of the important benefits of using a container/Pod orchestrator. When you create a Service in Kubernetes, controllers running behind the scenes create an entry in Kubernetes DNS records. Then other applications deployed in the cluster can look up the Service using its name. Kubernetes also configures routing within the cluster to send traffic for the Service to the Service’s ephemeral endpoint Pods.

Understanding Kubernetes DNS configuration and related traffic flow will help you troubleshoot problems accessing the cluster’s DNS from Pods. This is part one of a two-part deep-dive into how Kubernetes does this under the hood. In part one of this blog, we will look at how Kubernetes sets up DNS resolution for containers in Pods. In part two, we will look at how network traffic flows from containers in Pods for user workloads to the Pods providing DNS functionality. We’re going to use Kubernetes running under Docker Enterprise Edition for our examples in this blog.

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How Pods access Kubernetes DNS in Docker EE, part oneRead More »

How Pods access Kubernetes DNS in Docker EE, part one Read More »

What is Container Orchestration – Kubernetes Version?

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In a previous post, What is Container Orchestration?, I explained container orchestration using some examples based on Docker Swarm. While Docker Swarm is undeniably easier to both use and explain, Kubernetes is by far the most prevalent container orchestrator today. So, I’m going to go through the same examples from that previous post but, this time, use Kubernetes. One of the great things about Docker Enterprise is it supports both Swarm and Kubernetes so I didn’t have to change my infrastructure at all.

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What is Container Orchestration – Kubernetes Version?Read More »

What is Container Orchestration – Kubernetes Version? Read More »

Configure Custom CIDR Ranges in Docker EE

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I recently worked with a customer to customize all of the default Classless Interdomain Routing (CIDR) ranges used for IP address allocation by Docker Enterprise Edition 3.0 (Docker EE 3.0). The customer primarily wanted to document the customization process for future use. However, there is often a real need to change some of the default CIDR ranges to avoid conflicts with existing private IP addresses already in use within a customer’s network. Typically such a conflict will make it impossible for applications running in containers or pods to access external hosts in the conflicting CIDR range.

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Configure Custom CIDR Ranges in Docker EERead More »

Configure Custom CIDR Ranges in Docker EE Read More »

Auto Scaling Docker Nodes in AWS

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ButterBall Turkey

I once heard a story from someone who worked at ConAgra. They produce and sell a variety of food products that you and I eat all the time. The most notorious is the ButterBall turkey. ConAgra owned Butterball from 1990 to 2006. Every Thanksgiving holiday, so I am told, ButterBall would have to scale up their call-center as well as their website to a couple hundred web servers to handle the demand for “how to cook my turkey?” That’s a lot of hardware!

We are only a couple months away from Thanksgiving. So, what do you call a turkey on the day after Thanksgiving? Lucky. #dadjoke

 

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Auto Scaling Docker Nodes in AWSRead More »

Auto Scaling Docker Nodes in AWS Read More »

Interlock Service Clusters – with Code!

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So a colleague of mine was helping his client configure Interlock and wanted to know more about how to configure Interlock Service Clusters.  So I referred him to my previous blog – Interlock Service Clusters.  While that article conceptually helps someone understand the capabilities of Interlock, it does not show any working code examples.

Let’s review what Docker Enterprise UCP Interlock provides. And then I will show you how to configure Interlock to support multiple ingresses each of which are tied to its own environment.

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Interlock Service Clusters – with Code!Read More »

Interlock Service Clusters – with Code! Read More »

Attack of the Kubernetes Clones

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One of the customers I support is using Kubernetes under Docker EE UCP (Enterprise Edition Universal Control Plane) and has been very impressed with its stability and ease of management. Recently, however, a worker node that had been very stable for months started evicting Kubernetes pods extremely frequently, reporting inadequate CPU resources. Our DevOps team was still experimenting with determining resource requirements for many of their containerized apps, so at first, we thought the problem was caused by resource contention between pods running on the node.

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Attack of the Kubernetes ClonesRead More »

Attack of the Kubernetes Clones Read More »

Kubernetes Network Isolation

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In the 1980s there was a funny television commercial for an insurance company that was debauching many other insurance companies. These hideous competitors trained their agents to “Say NO, deny the Claim!” thereby denying customers the benefits of the insurance policy they had purchased. It always made me chuckle and I still remember the chant to this day. I want to show you how you can do this, “Say no, deny pod access!” in Kubernetes using NetworkPolicies applied to your application deployments.

Kubernetes Network Isolation
Denied

Recently while working with a customer who is quite new to Docker and the world of Kubernetes, they were inquiring about how to isolate their applications from each other in a shared Kubernetes cluster.

In a previous blog post entitled Kubernetes Workload Isolation I discussed how customers have segmented their cluster by using a combination of VLAN’s, Collections, and Namespaces. But if you are not utilizing VLAN’s to segment your networking among VM’s and if you are not using Collections to separate VM’s into different RBAC groups then you will need a different approach.

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Kubernetes Network IsolationRead More »

Kubernetes Network Isolation Read More »

What is Container Orchestration?

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Over the last two or three years I’ve given a similar presentation on containers to operations groups at clients, potential clients, conferences and meetups. Generally, they’re just getting started with containers and are wondering what orchestration is and how it impacts them. In this post, I will talk about what container orchestration is and provide several videos with simple examples of what it means.

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What is Container Orchestration?Read More »

What is Container Orchestration? Read More »

Kubernetes Workload Isolation

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There are many images of ships with pin-wheel colored containers in a myriad of stacked configurations. In the featured image above you can clearly see three ships at dock loaded with containers. These ships have unique destination port cities across the globe each one carrying a distinct set of product for a discreet set of customers. These containers carry a payload.

Our virtual docker containers carry a workload. So, the ships vary in what containers they carry, where they are transporting it, and for whom it belongs to. We will talk about how to get our virtual containers loaded into a particular ship and entertain one solution to VM and container isolation.

Over the years Capstone has work in many vertical industries. Several of Capstone’s customers have extremely regulated environments such as the banking, insurance, and financial investment industries. These industry verticals typically need to comply with numerous governing standards and often have unique ways of interpreting and applying those regulations to there IT infrastructure. All of these regulations are aimed at restricting, or at least minimizing, covert intrusion.

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Kubernetes Workload IsolationRead More »

Kubernetes Workload Isolation Read More »

Kubernetes NetworkPolicies in Docker Enterprise Edition

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Kubernetes running under Docker UCP uses the Calico CNI plugin so that you can use Kubernetes NetworkPolicies to control pod to pod communication as well as communication between pods and other network endpoints.

This blog post will walk you through an example of configuring Kubernetes NetworkPolicies. We will block traffic from one namespace into another namespace, while still allowing external traffic to access the “restricted” namespace. As a high-level use case, we will consider the situation where a development team is working on multiple branches of a project, and the pods in the different branches should not be able to communicate with each other. If you are not familiar with the basic concepts of NetworkPolicies, see the Kubernetes documentation here.

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Kubernetes NetworkPolicies in Docker Enterprise EditionRead More »

Kubernetes NetworkPolicies in Docker Enterprise Edition Read More »