tune cobbler and dnsmasq for larger deployments

[Matthew Mosesohn]

This may be converted to a blueprint after some discussion.

I propose to tune DHCP in the following ways:
* Set dhcp lease time for bootstrap to 10m
* Set dhcp lease time for node provisioning to 2H - more than enough time to complete provisioning without the first renew at T1 (60m)
* max leases should be 5120 (up from 1000)
* TFTP max connections should be 2048 (up from 50)
* Raise cache size to 2048 (up from 150) - only relevant for caching DNS forward requests

[Bogdan Dobrelya (bogdando)]

I agree, timeouts should be increased. By the way, would it as well resolve PXE issue then using bonds for admin interfaces? https://bugs.launchpad.net/fuel/+bug/1347869

[Bogdan Dobrelya (bogdando)]

Related https://bugs.launchpad.net/fuel/+bug/1381266

[Bogdan Dobrelya (bogdando)]

Raised to high due to 100 nodes feature relies on that change

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sergii Golovatiuk (<email address hidden>) on branch: master
Review: https://review.openstack.org/128939

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/129203

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/129203
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=3070f3fa3c6d1b227242fd2a00a7babfc73424f5
Submitter: Jenkins
Branch: master

commit 3070f3fa3c6d1b227242fd2a00a7babfc73424f5
Author: Sergii Golovatiuk <email address hidden>
Date: Thu Oct 16 16:27:18 2014 +0200

    Increase settings for dnsmasq and sysctl

    * Make a new variable dhcp_lease_max. It increases the number of
      available leases from 1000 to 1800. It allows to provision nodes on
      scale, when Debian Installer or Anaconda looses IP in the middle of
      install.
    * Make a new variable lease_time. It increases the default lease size
      to 120m, up from the default 60m.
    * Add cache-size to dnsmasq template. dnsmasq will keep more entries in
      case.
    * Increased neighbour table on master node to keep more ARP requests
      that come in parallel once deployment is started. This change also
      removes unneed broadcast traffic. New values are:
      net.ipv4.neigh.default.gc_thresh1 = 256
      net.ipv4.neigh.default.gc_thresh2 = 1024
      net.ipv4.neigh.default.gc_thresh3 = 2048
    * Fix linting

    Related-Bug: #1376680
    Related-Bug: #1379917
    Related-Bug: #1381997
    blueprint 100-nodes-support
    DocImpact

    Change-Id: I4da8070143e401f7a9246e72eda35e601b8c6386

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/5.1
Review: https://review.openstack.org/129850

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/129850
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=0e0479727e2240f8c51eb899435bac505377e245
Submitter: Jenkins
Branch: stable/5.1

commit 0e0479727e2240f8c51eb899435bac505377e245
Author: Sergii Golovatiuk <email address hidden>
Date: Thu Oct 16 16:27:18 2014 +0200

    Increase settings for dnsmasq and sysctl

    * Make a new variable dhcp_lease_max. It increases the number of
      available leases from 1000 to 1800. It allows to provision nodes on
      scale, when Debian Installer or Anaconda looses IP in the middle of
      install.
    * Make a new variable lease_time. It increases the default lease size
      to 120m, up from the default 60m.
    * Add cache-size to dnsmasq template. dnsmasq will keep more entries in
      case.
    * Increased neighbour table on master node to keep more ARP requests
      that come in parallel once deployment is started. This change also
      removes unneed broadcast traffic. New values are:
      net.ipv4.neigh.default.gc_thresh1 = 256
      net.ipv4.neigh.default.gc_thresh2 = 1024
      net.ipv4.neigh.default.gc_thresh3 = 2048
    * Fix linting

    Related-Bug: #1376680
    Related-Bug: #1379917
    Related-Bug: #1381997
    blueprint 100-nodes-support

    Change-Id: I4da8070143e401f7a9246e72eda35e601b8c6386