From 9df04fed70eb9f9e84f6da2ac5bb4d94df037fe6 Mon Sep 17 00:00:00 2001
From: Jean-Philippe Evrard <jean-philippe.evrard@belnet.be>
Date: Fri, 21 Aug 2015 12:56:30 +0200
Subject: [PATCH] Fixing haproxy-playbook fails when installing on multiple
 hosts

This bug is triggered when haproxy is deployed on multiple hosts
and external_lb_vip is different than the internal one.
As all host receive the same configuration, and are expected
to restart the haproxy service more than once
(once during role and once post_tasks), the playbook will fail,
because the restart of the service fails. The restart of the
service fails on some hosts because haproxy tries to
start/bind to an ip the host doesn't have (avoiding ip conflicts)

This allows haproxy to bind on non_local addresses by
addng a sysctl change in the playbook: net.ipv4.ip_nonlocal_bind = 1
The sysctl is changed for the containers/systems
when external_lb_vip is different than internal address and
the number of haproxy hosts is more than one thanks to a group_var.

Side-effect: other services are able to bind on non-local addresses
if the sysctl is changed.

This could be overriden by setting the variable haproxy_bind_on_non_local
in your user_* variables. If set to false, then the ip_non_local_bind
sysctl won't be changed.

Closes-Bug: #1487409

Change-Id: I41b3a5a4ba2d48192b505e3720456a77484aa92b
---
 playbooks/inventory/group_vars/hosts.yml                  | 3 +++
 playbooks/roles/haproxy_server/defaults/main.yml          | 1 +
 playbooks/roles/haproxy_server/tasks/haproxy_install.yml  | 2 +-
 .../roles/haproxy_server/tasks/haproxy_post_install.yml   | 8 ++++++++
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/playbooks/inventory/group_vars/hosts.yml b/playbooks/inventory/group_vars/hosts.yml
index 83998996a6..ef6639191b 100644
--- a/playbooks/inventory/group_vars/hosts.yml
+++ b/playbooks/inventory/group_vars/hosts.yml
@@ -226,3 +226,6 @@ swift_system_shell: /bin/bash
 swift_system_comment: swift system user
 swift_system_home_folder: "/var/lib/{{ swift_system_user_name }}"
 swift_service_region: "{{ service_region }}"
+
+## HAProxy
+haproxy_bind_on_non_local: "{% if groups.haproxy_hosts[1] is defined and internal_lb_vip_address != external_lb_vip_address %}True{% else %}False{% endif %}"
diff --git a/playbooks/roles/haproxy_server/defaults/main.yml b/playbooks/roles/haproxy_server/defaults/main.yml
index bab6861a15..161dab0ac2 100644
--- a/playbooks/roles/haproxy_server/defaults/main.yml
+++ b/playbooks/roles/haproxy_server/defaults/main.yml
@@ -67,6 +67,7 @@ haproxy_backup_nodes: []
 #         - "httplog"
 
 galera_monitoring_user: monitoring
+haproxy_bind_on_non_local: False
 
 ## haproxy SSL
 haproxy_ssl: no
diff --git a/playbooks/roles/haproxy_server/tasks/haproxy_install.yml b/playbooks/roles/haproxy_server/tasks/haproxy_install.yml
index 4226bdde56..9e78269ce1 100644
--- a/playbooks/roles/haproxy_server/tasks/haproxy_install.yml
+++ b/playbooks/roles/haproxy_server/tasks/haproxy_install.yml
@@ -24,7 +24,7 @@
   tags:
     - haproxy-apt-packages
 
-- name: Install HAPRoxy Packages
+- name: Install HAProxy Packages
   apt:
     pkg: "{{ item }}"
     state: latest
diff --git a/playbooks/roles/haproxy_server/tasks/haproxy_post_install.yml b/playbooks/roles/haproxy_server/tasks/haproxy_post_install.yml
index 7bf26033f8..5105021aa7 100644
--- a/playbooks/roles/haproxy_server/tasks/haproxy_post_install.yml
+++ b/playbooks/roles/haproxy_server/tasks/haproxy_post_install.yml
@@ -13,6 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Make haproxy bindable on non local addresses
+  sysctl:
+    name: net.ipv4.ip_nonlocal_bind
+    value: 1
+    sysctl_set: yes
+    state: present
+  when: haproxy_bind_on_non_local | bool
+
 - name: Drop base haproxy config
   template:
     src: "{{ item }}"