Add Flannel support (#814)

* Add flannel support

* Document Flannel SDN use case for a separate data network.
* Add post install step for flannel SDN
* Configure iptables rules as described for OCP 3.4 refarch
  https://access.redhat.com/documentation/en-us/reference_architectures/2017/html/deploying_red_hat_openshift_container_platform_3.4_on_red_hat_openstack_platform_10/emphasis_manual_deployment_emphasis#run_ansible_installer

* Configure flannel interface options

Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>

* Use os_firewall from galaxy for required flannel rules

For flannel SDN:
* Add openshift-ansible as a galaxy dependency module.
* Use openshift-ansible/roles/os_firewall to apply DNS rules
  for flanel SDN.
* Apply the remaining advanced rules with direct
  iptables commands as os_firewall do not support advanced rules.
* Persist only iptables rules w/o dynamic KUBe rules. Those are
  added runtime and need restoration after reboot or iptables restart.
* Configure and enable the masked iptables service on the app nodes.
  Enable it to allow the in-memory rules to be persisted.
  Disable firewalld, which is the expected default behavior of the
  os_firewall module.

Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>

* Allow access from nodes to masters' port 2379 when using flannel

Flannel requires to gather information from etcd to configure and
assign the subnets in the nodes, therefore, allow access from nodes to port 2379/tcp to the master security group.

Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>

5 files changed, 108 insertions, 0 deletions

diff --git a/playbooks/provisioning/openstack/README.md b/playbooks/provisioning/openstack/README.md
index b9a3b23de..a277047e1 100644
--- a/playbooks/provisioning/openstack/README.md
+++ b/playbooks/provisioning/openstack/README.md
@@ -145,6 +145,26 @@ via the public IP of the server. You can not send updates via the private
 IP yet. This forces the in-stack private server to have a floating IP.
 See also the [security notes](#security-notes)
 
+#### Flannel networking
+
+In order to configure the
+[flannel networking](https://docs.openshift.com/container-platform/3.6/install_config/configuring_sdn.html#using-flannel),
+uncomment and adjust the appropriate `inventory/group_vars/OSEv3.yml` group vars.
+Note that the `osm_cluster_network_cidr` must not overlap with the default
+Docker bridge subnet of 172.17.0.0/16. Or you should change the docker0 default
+CIDR range otherwise. For example, by adding `--bip=192.168.2.1/24` to
+`DOCKER_NETWORK_OPTIONS` located in `/etc/sysconfig/docker-network`.
+
+Also note that the flannel network will be provisioned on a separate isolated Neutron
+subnet defined from `osm_cluster_network_cidr` and having ports security disabled.
+Use the `openstack_private_data_network_name` variable to define the network
+name for the heat stack resource.
+
+After the cluster deployment done, you should run an additional post installation
+step for flannel and docker iptables configuration:
+
+   ansible-playbook openshift-ansible-contrib/playbooks/provisioning/openstack/post-install.yml
+
 #### Other configuration variables
 
 `openstack_ssh_key` is a Nova keypair - you can see your keypairs with
diff --git a/playbooks/provisioning/openstack/galaxy-requirements.yaml b/playbooks/provisioning/openstack/galaxy-requirements.yaml
index 93dd14ec2..1d745dcc3 100644
--- a/playbooks/provisioning/openstack/galaxy-requirements.yaml
+++ b/playbooks/provisioning/openstack/galaxy-requirements.yaml
@@ -4,3 +4,7 @@
 # From 'infra-ansible'
 - src: https://github.com/redhat-cop/infra-ansible
   version: master
+
+# From 'openshift-ansible'
+- src: https://github.com/openshift/openshift-ansible
+  version: master
diff --git a/playbooks/provisioning/openstack/post-install.yml b/playbooks/provisioning/openstack/post-install.yml
new file mode 100644
index 000000000..417813e2a
--- /dev/null
+++ b/playbooks/provisioning/openstack/post-install.yml
@@ -0,0 +1,57 @@
+---
+- hosts: OSEv3
+  gather_facts: False
+  become: True
+  tasks:
+    - name: Save iptables rules to a backup file
+      when: openshift_use_flannel|default(False)|bool
+      shell: iptables-save > /etc/sysconfig/iptables.orig-$(date +%Y%m%d%H%M%S)
+
+# Enable iptables service on app nodes to persist custom rules (flannel SDN)
+# FIXME(bogdando) w/a https://bugzilla.redhat.com/show_bug.cgi?id=1490820
+- hosts: app
+  gather_facts: False
+  become: True
+  vars:
+    os_firewall_allow:
+      - service: dnsmasq tcp
+        port: 53/tcp
+      - service: dnsmasq udp
+        port: 53/udp
+  tasks:
+    - when: openshift_use_flannel|default(False)|bool
+      block:
+        - include_role:
+            name: openshift-ansible/roles/os_firewall
+        - include_role:
+            name: openshift-ansible/roles/lib_os_firewall
+        - name: set allow rules for dnsmasq
+          os_firewall_manage_iptables:
+            name: "{{ item.service }}"
+            action: add
+            protocol: "{{ item.port.split('/')[1] }}"
+            port: "{{ item.port.split('/')[0] }}"
+          with_items: "{{ os_firewall_allow }}"
+
+- hosts: OSEv3
+  gather_facts: False
+  become: True
+  tasks:
+    - name: Apply post-install iptables hacks for Flannel SDN (the best effort)
+      when: openshift_use_flannel|default(False)|bool
+      block:
+        - name: set allow/masquerade rules for for flannel/docker
+          shell: >-
+            (iptables-save | grep -q custom-flannel-docker-1) ||
+            iptables -A DOCKER -w
+            -p all -j ACCEPT
+            -m comment --comment "custom-flannel-docker-1";
+            (iptables-save | grep -q custom-flannel-docker-2) ||
+            iptables -t nat -A POSTROUTING -w
+            -o {{flannel_interface|default('eth1')}}
+            -m comment --comment "custom-flannel-docker-2"
+            -j MASQUERADE
+
+        # NOTE(bogdando) the rules will not be restored, when iptables service unit is disabled & masked
+        - name: Persist in-memory iptables rules (w/o dynamic KUBE rules)
+          shell: iptables-save | grep -v KUBE > /etc/sysconfig/iptables
diff --git a/playbooks/provisioning/openstack/post-provision-openstack.yml b/playbooks/provisioning/openstack/post-provision-openstack.yml
index a80e8d829..e460fbf12 100644
--- a/playbooks/provisioning/openstack/post-provision-openstack.yml
+++ b/playbooks/provisioning/openstack/post-provision-openstack.yml
@@ -76,6 +76,16 @@
   hosts: OSEv3
   gather_facts: true
   become: true
+  vars:
+    interface: "{{ flannel_interface|default('eth1') }}"
+    interface_file: /etc/sysconfig/network-scripts/ifcfg-{{ interface }}
+    interface_config:
+      DEVICE: "{{ interface }}"
+      TYPE: Ethernet
+      BOOTPROTO: dhcp
+      ONBOOT: 'yes'
+      DEFTROUTE: 'no'
+      PEERDNS: 'no'
   pre_tasks:
     - name: "Include DNS configuration to ensure proper name resolution"
       lineinfile:
@@ -83,6 +93,21 @@
         dest: /etc/sysconfig/network
         regexp: "IP4_NAMESERVERS={{ hostvars['localhost'].private_dns_server }}"
         line: "IP4_NAMESERVERS={{ hostvars['localhost'].private_dns_server }}"
+    - name: "Configure the flannel interface options"
+      when: openshift_use_flannel|default(False)|bool
+      block:
+        - file:
+            dest: "{{ interface_file }}"
+            state: touch
+            mode: 0644
+            owner: root
+            group: root
+        - lineinfile:
+            state: present
+            dest: "{{ interface_file }}"
+            regexp: "{{ item.key }}="
+            line: "{{ item.key }}={{ item.value }}"
+          with_dict: "{{ interface_config }}"
   roles:
     - node-network-manager
 
diff --git a/playbooks/provisioning/openstack/sample-inventory/group_vars/OSEv3.yml b/playbooks/provisioning/openstack/sample-inventory/group_vars/OSEv3.yml
index 70e77662d..949a323a7 100644
--- a/playbooks/provisioning/openstack/sample-inventory/group_vars/OSEv3.yml
+++ b/playbooks/provisioning/openstack/sample-inventory/group_vars/OSEv3.yml
@@ -53,5 +53,7 @@ openshift_override_hostname_check: true
 ansible_become: true
 
 # # Flannel networking
+#osm_cluster_network_cidr: 10.128.0.0/14
 #openshift_use_openshift_sdn: false
 #openshift_use_flannel: true
+#flannel_interface: eth1