Reorder hostfile insertion to support upgrades

When upgrading from a /etc/hosts file created before commit
ae02667b84 the old entries were not
removed on the first run. The hostname generation had to be run again to
remove them.

Reordering the if statement ensures that existing entries are changed
instead of adding new entries for the same IP address and that
duplicate entries are removed in all cases.

Change-Id: I2a21d13310b457e91a090541ae7f02f974413965

templates/openstack-host-hostfile-setup.sh.j2

@@ -6,12 +6,12 @@ set -x
 function insert_host_entry {
     ENTRY=$1
     ADDR=$2
-    if ! grep -q -o "^${ENTRY}$" /etc/hosts; then
+    if [[ "$(grep "^${ADDR}\b" /etc/hosts | wc -l)" -ge "2" ]]; then
+      sed -i "/^${ADDR}\b/d" /etc/hosts
       echo "${ENTRY}" | tee -a /etc/hosts
-    elif ! grep -q -o "^${ADDR}\b" /etc/hosts; then
+    elif grep -q "^${ADDR}\b" /etc/hosts; then
       sed -i "s|^${ADDR}\b\ .*|${ENTRY}|" /etc/hosts
-    elif [[ "$(grep -o "^${ADDR}\b" /etc/hosts | wc -l)" -ge "2" ]]; then
-      sed -i "/^${IPADDR}\b/d" /etc/hosts
+    elif ! grep -q "^${ENTRY}$" /etc/hosts; then
       echo "${ENTRY}" | tee -a /etc/hosts
     fi
 }

tests/inventory

@@ -2,10 +2,12 @@
 localhost ansible_host=127.0.0.1 ansible_become=True
 test1 ansible_host=127.111.111.101 ansible_become=True
 test2 ansible_host=127.111.111.102 ansible_become=True
+test3 ansible_host=127.111.111.103 ansible_become=True
 
 [all_containers]
 test1
 test2
+test3
 
 [hosts]
 localhost

tests/test.yml

@@ -13,6 +13,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Playbook for test setup
+  hosts: localhost
+  connection: local
+  gather_facts: false
+  tasks:
+    - name: Add entries to hosts file
+      blockinfile:
+        dest: /etc/hosts
+        block: |
+          127.111.111.102 test2
+          127.111.111.103 test3.openstack.local
+          127.111.111.103 test3.additional
+        marker: ""
+
 - include: "common/test-install-openstack-hosts.yml"
 
 - name: Playbook for role testing
@@ -61,6 +75,8 @@
           - "'vm.swappiness' in sysctl_content"
           - "'127.111.111.101 test1.openstack.local test1' in hosts_content"
           - "'127.111.111.102 test2.openstack.local test2' in hosts_content"
+          - "'127.111.111.103 test3.openstack.local test3' in hosts_content"
+          - "'127.111.111.103 test3.additional' not in hosts_content"
           - "'127.0.1.1 localhost.openstack.local localhost' in hosts_content"
           - "release_file.stat.exists"
           - "systat_file.stat.exists"