Discover Docker, K8s and Hashicorp Nomad with Maksym Prokopov

The new kid on the orchestration block – Hashicorp Nomad

Mon, 01 Jan 2024 11:48:22 +0100

One binary (tm) for client and server
Uses own RAFT implementation for clustering
Supports HCL for resource definition and templating, same as terraform! Way better at DRY configuration.
Supports not only docker, but raw JAR deployments, etc.
Doesn’t have any ingress management. Though, integrates very nicely with Traefik using native facilities.

This is currently my orchestration tool of choice for running anything in own cluster.

Remove old docker images one line

Mon, 15 Aug 2022 18:04:02 +0100

docker rmi xxxxxxxxxxx.dkr.ecr.eu-central-1.amazonaws.com/it-service-app:2.6.{234..295}

this will remove all the images ranged from 2.6.234 till 2.6.295

Docker logrotate

Tue, 25 Jan 2022 08:29:49 +0100

Actually you don’t need any logrotate for docker, as it has built-in.

Just set to this /etc/docekr/daemon.json

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3" 
  }
}

max-sizeNo-1The maximum size of the log before it is rolled. A positive integer plus a modifier representing the unit of measure (k, m, or g). Defaults to -1 (unlimited). This is used by json-log required to keep the docker log command working.
max-fileNo1The maximum number of log files that can be present. If rolling the logs creates excess files, the oldest file is removed. Only effective when max-size is also set. A positive integer. Defaults to 1.

initContainer and rabbit mq checks in k8s pod

Thu, 04 Nov 2021 11:29:26 +0100

Sometimes you need to implement ordered loading for the pods. Say, launch rabbit mq container first, than your app container. This could be done using initContainer concept.

Put this into values.yaml of your helm chart definition

rabbit:
  host: rabbit

and this to the app deployment.yaml definition

initContainers:
        - name: check-rabbit-ready
          image: public.ecr.aws/runecast/busybox:1.33.1
          command: ['sh', '-c', 'until nc -vz {{ .Values.rabbit.host }} 5672; do echo "Waiting for rabbit service"; sleep 2; done;']

get pods on the node from particular AZ

Thu, 21 Oct 2021 07:59:20 +0100

For Amazon EKS:

kubectl describe nodes -l topology.kubernetes.io/zone=eu-central-1a

find all and empty log files oneliner

Fri, 17 Sep 2021 08:32:19 +0100

find . -name *.log | xargs truncate -s0

Ansible remove False variables from environment

Tue, 14 Sep 2021 08:38:01 +0100

Use the following code snippet:

telegram:
  enabled: False

Env:
  - TELEGRAM_NOTIFICATION={{ telegram.enabled | ternary('true', None)}}

In this way False value evaluates to None and as outcome you’ll get empty TELEGRAM_NOTIFICATION variable

remove exited containers from docker

Sat, 11 Sep 2021 16:37:11 +0100

docker ps -f status=exited -q | xargs docker rm

Execute eksctl from terraform

Fri, 27 Aug 2021 12:00:07 +0100

cluster_name and profile are terraform variables

resource "null_resource" "oidc_provider" {
  triggers = {
    cluster_name = var.cluster_name
  }

  provisioner "local-exec" {
    command = <<EOF
AWS_PROFILE=${var.profile} eksctl utils associate-iam-oidc-provider --cluster ${var.cluster_name} --approve
EOF
  }
}

Check result with command

aws iam list-open-id-connect-providers | jq ".OpenIDConnectProviderList[].Arn"

aws list ec2 instances by tag

Thu, 29 Jul 2021 15:54:05 +0100

simple ec2 instances list using jq

aws ec2 describe-instances | jq -r '.Reservations | .[].Instances | .[].Tags | .[] | select(.Key == "Name") | .Value'

enable gitea to use ssh port 22

Sat, 23 Jan 2021 12:59:40 +0100

Move original ssh service to other port, like 2022
set gitea config to use port 22
app.ini

[server]
DISABLE_SSH      = false
SSH_PORT         = 22
SSH_LISTEN_HOST  = 0.0.0.0
SSH_LISTEN_PORT  = 22
START_SSH_SERVER = true

execute

sudo setcap CAP_NET_BIND_SERVICE=+eip /usr/local/bin/gitea to enable usage of the port 22

copy files having search string to the target folder

Tue, 17 Nov 2020 17:06:45 +0100

let’s say you have true in the hundreds of files and you need to copy only those which contain this string, it is quite easy to do with Linux find utility

grep -l -ri -m1 "Active>true" */*.xml | xargs -I {} cp {} target_folder

recursive copy of the file with same name to the folder

Mon, 02 Nov 2020 16:53:03 +0100

find . -type f -name coverage.cov -exec bash -c 'cp {} $(pwd)/.coverage/cov/${RANDOM}.cov' \;

macos datomic console in background plist

Mon, 02 Nov 2020 08:09:43 +0100

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.cognitect.datomic-console</string>
  <key>ProgramArguments</key>
  <array>
     <string>/Users/nexus/datomic-pro-1.0.6165/bin/console</string>
     <string>stock</string>
     <string>datomic:dev://localhost:4334/stock</string>
     <string>--port</string>
     <string>8080</string>
  </array>
<key>WorkingDirectory</key>
<string>/Users/nexus/datomic-pro-1.0.6165</string>
</dict>
</plist>

macos run datomic in background plist

Mon, 02 Nov 2020 08:08:58 +0100

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.cognitect.datomic</string>
  <key>ProgramArguments</key>
  <array>
     <string>/Users/nexus/datomic-pro-1.0.6165/bin/transactor</string>
     <string>config/dev-transactor.properties</string>
  </array>
<key>WorkingDirectory</key>
<string>/Users/nexus/datomic-pro-1.0.6165</string>
</dict>
</plist>

quicky find macos version from the command line

Tue, 27 Oct 2020 12:23:56 +0100

just use sw_vers command

# sw_vers
ProductName:Mac OS X
ProductVersion:10.15.7
BuildVersion:19H2

enable GraalVM for macos Catalina gatekeeper

Fri, 16 Oct 2020 12:20:22 +0100

sudo xattr -r -d com.apple.quarantine /Library/Java/JavaVirtualMachines/graalvm-ce-java11-20.2.0/

Ansible add entries to .htpassword

Tue, 29 Sep 2020 11:49:00 +0100

There are several ways to do this:

Use template action and use template file
Use array of entries and loop with lininfile command
Use https://docs.ansible.com/ansible/latest/collections/community/general/htpasswd_module.html htpasswd module.

I decided to go with approach #2.
in variables

htpasswd:
  - user1:password1
  - user2:password2

in the playbook

- name: set password file
      lineinfile:
        path: "{{ webroot }}/shared/.htpasswd"
        line: "{{ item }}"
        create: yes
      when: oxid.configuration == "production"
      loop: "{{ htpasswd }}"

CentOS 7 upgrade Jenkins with no key check

Thu, 11 Jun 2020 10:18:04 +0100

yum upgrade jenkins --nogpgcheck

can not install docker-compose on CentOS 7

Thu, 11 Jun 2020 09:51:55 +0100

CentOS 7 fix for UserWarning: Unknown distribution option: ‘python_requires’

yum install -y python-pip python-devel gcc
pip install docker-compose