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Ansible role for installing etcd cluster
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ansible-role-etcd

This Ansible playbook is used in Kubernetes the not so hard way with Ansible - etcd cluster. Have a look there for more information.

Installes a etcd cluster. HINT: This playbook does NOT reload or restart the etcd cluster nodes after the systemd service file was changed! This is intentional! It would be a very bad idea to restart all etcd nodes at the same time. So if the etcd.service file has changed restart/reload etcd by hand one node after the other and check log output if the node joined the cluster again afterwards! As a side node: The script will issue a systemctl daemon-reload after the etcd service file was changed so that at least systemd is aware of the changed file and you don't take care about that. So a reboot of a etcd node would also active the new configuration.

Versions

I tag every release and try to stay with semantic versioning. If you want to use the role I recommend to checkout the latest tag. The master branch is basically development while the tags mark stable releases. But in general I try to keep master in good shape too. A tag 7.0.0+3.2.24 means this is release 7.0.0 of this role and it's meant to be used with etcd version 3.2.24 (but should we newer versions also). If the role itself changes X.Y.Z before + will increase. If the etcd version changes X.Y.Z after + will increase. This allows to tag bugfixes and new major versions of the role while it's still developed for a specific etcd release.

Changelog

see CHANGELOG.md

Requirements

This playbook requires that you already created some certificates for etcd (see Kubernetes the not so hard way with Ansible - Certificate authority (CA)). The playbook searches the certificates in etcd_ca_conf_directory on the host this playbook runs.

Role Variables

# The directory from where to copy the etcd certificates. By default this
# will expand to user's LOCAL $HOME (the user that run's "ansible-playbook ..."
# plus "/etcd-certificates". That means if the user's $HOME directory is e.g.
# "/home/da_user" then "etcd_ca_conf_directory" will have a value of
# "/home/da_user/etcd-certificates".
etcd_ca_conf_directory: "{{ '~/etcd-certificates' | expanduser }}"

# etcd version
etcd_version: "3.3.13"
# Port where etcd listening for clients
etcd_client_port: "2379"
# Port where etcd is listening for it's peer's
etcd_peer_port: "2380"
# Interface to bind etcd ports to
etcd_interface: "tap0"
# Directroy for etcd configuration
etcd_conf_dir: "/etc/etcd"
# Directory to store downloaded etcd archive
# Should not be deleted to avoid downloading over and over again
etcd_download_dir: "/opt/etcd"
# Directroy to store etcd binaries
etcd_bin_dir: "/usr/local/bin"
# etcd data directory (etcd database files so to say)
etcd_data_dir: "/var/lib/etcd"

# etcd flags/settings. This parameters are directly passed to "etcd" daemon during startup.
# To see all possible settings/flags either run "etcd --help" or have a look at the
# documentation. The dictionary keys below are just the flag names without "--". E.g.
# the first "name" flag below will be passed as "--name=whatever-hostname" to "etcd"
# daemon.
etcd_settings:
  "name": "{{ansible_hostname}}"
  "cert-file": "{{etcd_conf_dir}}/cert-etcd.pem"
  "key-file": "{{etcd_conf_dir}}/cert-etcd-key.pem"
  "peer-cert-file": "{{etcd_conf_dir}}/cert-etcd.pem"
  "peer-key-file": "{{etcd_conf_dir}}/cert-etcd-key.pem"
  "peer-trusted-ca-file": "{{etcd_conf_dir}}/ca-etcd.pem"
  "peer-client-cert-auth": "true" # # Enable peer client cert authentication
  "client-cert-auth": "true" # Enable client cert authentication
  "trusted-ca-file": "{{etcd_conf_dir}}/ca-etcd.pem"
  "advertise-client-urls": "{{'https://' + hostvars[inventory_hostname]['ansible_' + etcd_interface].ipv4.address + ':' + etcd_client_port}}"
  "initial-advertise-peer-urls": "{{'https://' + hostvars[inventory_hostname]['ansible_' + etcd_interface].ipv4.address + ':' + etcd_peer_port}}"
  "listen-peer-urls": "{{'https://' + hostvars[inventory_hostname]['ansible_' + etcd_interface].ipv4.address + ':' + etcd_peer_port}}"
  "listen-client-urls": "{{'https://' + hostvars[inventory_hostname]['ansible_' + etcd_interface].ipv4.address + ':' + etcd_client_port + ',https://127.0.0.1:' + etcd_client_port}}"
  "initial-cluster-token": "etcd-cluster-0" # Initial cluster token for the etcd cluster during bootstrap.
  "initial-cluster-state": "new" # Initial cluster state ('new' or 'existing')
  "data-dir": "{{etcd_data_dir}}" # etcd data directory (etcd database files so to say)
  "wal-dir": "" # Dedicated wal directory ("" means no seperated WAL directory)
  "auto-compaction-retention": "0" # Auto compaction retention in hour. 0 means disable auto compaction.
  "snapshot-count": "100000" # Number of committed transactions to trigger a snapshot to disk
  "heartbeat-interval": "100" # Time (in milliseconds) of a heartbeat interval
  "election-timeout": "1000" # Time (in milliseconds) for an election to timeout. See tuning documentation for details
  "max-snapshots": "5" # Maximum number of snapshot files to retain (0 is unlimited)
  "max-wals": "5" # Maximum number of wal files to retain (0 is unlimited)
  "cors": "" # Comma-separated whitelist of origins for CORS (cross-origin resource sharing)
  "quota-backend-bytes": "0" # Raise alarms when backend size exceeds the given quota (0 defaults to low space quota)
  "log-package-levels": "" # Specify a particular log level for each etcd package (eg: 'etcdmain=CRITICAL,etcdserver=DEBUG')
  "log-output": "default" # Specify 'stdout' or 'stderr' to skip journald logging even when running under systemd

# Certificate authority and certificate files for etcd
etcd_certificates:
  - ca-etcd.pem        # client server TLS trusted CA key file/peer server TLS trusted CA file
  - ca-etcd-key.pem    # CA key file
  - cert-etcd.pem      # peer server TLS cert file
  - cert-etcd-key.pem  # peer server TLS key file

The etcd default settings defined in etcd_settings can be overriden by defining a variable called etcd_settings_user. You can also add additional settings by using this variable. E.g. to override the default value for log-output seting and add a new setting like grpc-keepalive-min-time add the following settings to group_vars/k8s.yml:

etcd_settings_user:
  "log-output": "stdout"
  "grpc-keepalive-min-time": "10s"

Example Playbook

- hosts: k8s_etcd
  roles:
    - githubixx.etcd

License

GNU GENERAL PUBLIC LICENSE Version 3

Author Information

http://www.tauceti.blog

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