devops - RicoJia/notes GitHub Wiki

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• multiple pods so you can horizontally scale for peak hours, instead of a single ec2 instance
  • create a cluster -> deploy app in pod, using CI/CD, or amazon ECR (container registery)
• load balancers:
  1. layer 4: transport layer (TCP/IP): IP address, port number, packet size
  2. Layer 7: application layer: depending on HTTP requests, distribute requests.
  3. working principle: round robin, least connections,
     • Do other things, like health check; SSL
     • can cache static content
  4. A pod is not an EC2 (a virtual machine )

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1. CI_COMMIT_TAG, CI_COMMIT_BRANCH are pre-defined.
2. can create a deb package. Which installs scripts to /usr/sbin:

   driver-armhf-build:
     script:
       - mkdir -p ${DEB_NAME}_${DEB_VERSION}${DEB_BRANCH_SUFFIX}_${DEB_ARCH}/usr/sbin
       - cp bash_scripts/* ${DEB_NAME}_${DEB_VERSION}${DEB_BRANCH_SUFFIX}_${DEB_ARCH}/usr/sbin/
   

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1. Ansible Basics: a role has a playbook, there's a tasks; yaml.

   • for deploying onto multiple robots
   • role: to group tasks together
   • playbook: yaml file that defines the desired states of systems.
     • task: small unit like install a package, start a service
     • tags: can pass to --tags tag1,tag2 ... so make it "_"
   • inventory: contains list of hosts to control, like moxis
   • update tasks with the script,
     • molecule tests, spins up a docker container. (how) - item potency? verge, run the role twice; should be no changes on the second test - like in math, f(x) = f(f(x)) - test itself. https://www.jeffgeerling.com/blog/2018/testing-your-ansible-roles-molecule molecule test --destroy=never molecule login

2. Ansible Env vars:

   1. Create liftnet_api_keys.yml
   2. encrypt it using ansible-vault encrypt filename
   3. ansible-playbook playbooks/robot_specific.yml -v -e site=$SITE -kK --limit $ROBOT

3. How to create API keys:

   1. make sure you can see the ansible-vault password on 1password

   2. If you are creating a yml file, do

      ansible-vault create <NAME>.yml
      

   3. Then, populate Yaml in the form. Or, you can take a look at existing examples, using the diligent credentials above

      ---
      
      FIELD: Value