Category: Systems Admin

  • Get access to a container in Kubernetes cluster

    With Kubernetes(K8s), there’s no need to do ssh [email protected] anymore since everything is running as containers. There are still occasions when I need shell access to a container to do some troubleshooting. With Docker I can do docker exec -ti <container_id> /bin/bash It’s quite similar in K8s kubectl exec -ti <container_id> — /bin/bash However in […]

  • Kops: Add Policies for Migrated Apps

    When migrating some old applications to a Kubernetes(k8s) cluster provisioned by kops, a lot of things might break and one of them is the missing policy for the node. By default, nodes of a k8s cluster have the following permissions: ec2:Describe* ecr:GetAuthorizationToken ecr:BatchCheckLayerAvailability ecr:GetDownloadUrlForLayer ecr:GetRepositoryPolicy ecr:DescribeRepositories ecr:ListImages ecr:BatchGetImage route53:ListHostedZones route53:GetChange // The following permissions are […]

  • Notes: BuildKite and Kubernetes Rolling Update

    This is kind of a textbook case that container is much more efficient than VM. The CI pipeline in comparison uses AWS CloudFormation to build new VMs and drain old VMs to do a rolling update, which takes around 10 minutes for everything even if it’s just 1 line of code changed. I did a […]

  • Why I like BuildKite

    BuildKite is a relative new CI toolkit I would like to replace Jenkins with. Here are some pros and cons I thought I could share: Pros: Designed with containers(docker) in mind. Hybrid architecture, console as a hosted service where agents can run anywhere with internet connectivity Build pipeline as code, also very easy to write […]

  • Play a bit Kubernetes with Minikube

    I’ve just played a bit Kubernetes on my Arch Linux laptop, with Minikube. It’s easier than I thought. Since I’ve already installed VirtualBox from the start, I can use minikube right after I installed it with curl -Lo minikube && chmod +x minikube && sudo mv minikube /usr/local/bin/ The command I used to start […]

  • Linux and Wake on LAN

    The Internet servers are usually on 24×7, probably that’s why I never had the need to use the Wake on LAN feature on a computer. I’ve just built a home server running Ubuntu Linux, using consumer grade PC parts. To avoid a big surge on my next electricity bill, I plan to only turn on […]

  • Install Fluentd with Ansible

    Fluentd has become the popular open source log aggregration framework for a while. I’ll try to give it a spin with Ansible. There are quite some existing Ansible playbooks to install Fluentd out there, but I would like to do it from scratch just to understand how it works. From the installation guide page, I […]

  • The Burnout Effect

    Back in October 2015 I got an offer from a big data startup, and after 1 year and 4 months I decided to move on. There’s a 3D printer and a drone in the office and the team was talking about Fallout 4 in the morning because it was just released. I thought the company […]