01_install_couchbase.yml

---
- name: Install Couchbase
  hosts:  all
  become_method: sudo
  tasks:
    - name: upgrade all packages
      become: yes
      yum:
        name: '*'
        state: latest
    
    - name: Install dependencies
      yum: name={{ item }} state=latest update_cache=yes
      become: yes
      with_items:
      - pkgconfig
      - openssl

    - name: Download Couchbase Repo definition
      become: yes
      get_url: dest=/tmp/couchbase-release-1.0-2-x86_64.rpm url=http://packages.couchbase.com/releases/couchbase-release/couchbase-release-1.0-2-x86_64.rpm 

    - name: Install Couchbase Repo definition
      become: yes
      yum: name=/tmp/couchbase-release-1.0-2-x86_64.rpm

    - name: Instructs the kernel to swap only as a last resort. Set this to 1 if on a kernel version > 3.0 vm.swappiness = 0
      become: yes
      sysctl: name=vm.swappiness value=1 state=present
      
    - name: Disable THP
      become: yes
      shell: "{{ item }}"
      with_items:
        - echo 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' >> /etc/rc.local
        - echo 'echo never > /sys/kernel/mm/transparent_hugepage/defrag' >> /etc/rc.local
        - echo never > /sys/kernel/mm/transparent_hugepage/enabled
        - echo never > /sys/kernel/mm/transparent_hugepage/defrag
        
    - name: Increase frequency of keepalive probes, identifiying and timing out dead connections faster
      become: yes
      sysctl: name=net.ipv4.tcp_keepalive_intvl value=30 state=present

    - name: Enables reuse of TIME-WAIT sockets to reduce the time spent constructing connections. This setting is safe for all Couchbase protocols. 
      become: yes
      sysctl: name=net.ipv4.tcp_tw_reuse value=1 state=present

      # The default 20% of total system memory can overwhelm the storage system # once flushed.
    - name: Limits the maximum memory used to 200MB before pdflush is involved.
      become: yes
      sysctl: name=vm.dirty_bytes value=209715200 state=present

    - name: The lower threshold for vm.dirty_bytes 
      become: yes
      sysctl: name=vm.dirty_background_bytes value=104857600 state=present

    - name: Increases the rate at which data is flushed to disk  vm.dirty_writeback_centisecs = 100
      become: yes
      sysctl: name=vm.dirty_expire_centisecs value=300 state=present

    - name: Increases the rate at which data is flushed to disk (2)
      become: yes
      sysctl: name=vm.dirty_writeback_centisecs value=100 state=present

    - name: Increases the max open file handles. 
      become: yes
      sysctl: name=fs.file-max value=500000 state=present

    - name: Disables NUMA zone reclaim algorithm. This tends to decrease read latencies. 
      become: yes
      sysctl: name=vm.zone_reclaim_mode value=0 state=present reload=yes


    - name: Install Couchbase Server
      become: yes
      yum: name=couchbase-server state=latest
      
    - name: Start Couchbase Server
      become: yes
      service: name=couchbase-server state=started
      
    - name: Wait for Couchbase initialization
      wait_for: port={{ couchbase_port }} delay=2
      
    - name: Check for numactl installed (but do not install it)
      become: yes
      yum:
        list: numactl
      register: numactl_reg
      
    - name: Make data dir... /cbdata
      become: yes
      file: path={{ data_path }} state=directory owner=couchbase group=couchbase mode=u=rwx,g=rx,o=
      
      
    # - name: Update init script with numactl (only if numactl is installed)
    #   become: yes
    #   replace:
    #     dest=/etc/init.d/couchbase-server
    #     regexp='daemon --user couchbase .DAEMON'
    #     replace='daemon --user couchbase "numactl --interleave=all $DAEMON"'
    #   when: (numactl_reg.results|length > 1) and (numactl_reg[1].yumstate == 'installed')
    #
    # - name: Restart Couchbase Server (with numactl)
    #   become: yes
    #   service: name=couchbase-server state=restarted
    #
    # - name: Wait for restarted Couchbase server
    #   wait_for: port={{ couchbase_port }} delay=2