From 78909146279976000205bd608c817bbe8079ce30 Mon Sep 17 00:00:00 2001
From: Mark Goddard <mark@stackhpc.com>
Date: Fri, 17 Apr 2020 11:59:16 +0100
Subject: [PATCH] Improve SSH known host error messages

A common failure early on when using Kayobe is during discovery of SSH
known hosts. This happens if a host does not have an IP address
configured on the admin (SSH) network. The failure looks like this:

PLAY [Ensure known hosts are configured]
**********************************************************************
TASK [ssh-known-host : Scan for SSH keys]
**********************************************************************
failed: [compute0 -> localhost] (item=) => {"ansible_loop_var": "item",
    "changed": false, "cmd": ["ssh-keyscan"], "delta": "0:00:00.013855",
    "end": "2020-04-17 10:51:01.857855", "item": "", "msg": "non-zero
        return code", "rc": 1, "start": "2020-04-17 10:51:01.844000",
    "stderr": "usage: ssh-keyscan [-46cDHv] [-f file] [-p port] [-T
        timeout] [-t type]\n\t\t   [host | addrlist namelist]",
    "stderr_lines": ["u sage: ssh-keyscan [-46cDHv] [-f file] [-p port]
        [-T timeout] [-t type]", "\t\t   [host | addrlist namelist]"],
        "stdout": "", "stdout_lines": []}

This happens when ansible_host is an empty string, typically because the
host has no IP address defined in for the admin network in
network-allocation.yml. This is very confusing for a new user. We should
provide a more informative message.

It's not exactly clear how a user gets to this point, since the
ip-allocation.yml playbook runs before ssh-known-host.yml, which should
populate network-allocation.yml.

This change detects this failure mode and provides a message with
information about how to resolve it.

Change-Id: I564b6e4509a30dec7c49a23bb2f75d490be775ed
Story: 2007566
Task: 39456
---
 ansible/roles/ssh-known-host/tasks/main.yml        | 14 ++++++++++++++
 ...rove-ssh-known-host-error-15fbc6ae4fa3dbd6.yaml |  6 ++++++
 2 files changed, 20 insertions(+)
 create mode 100644 releasenotes/notes/improve-ssh-known-host-error-15fbc6ae4fa3dbd6.yaml

diff --git a/ansible/roles/ssh-known-host/tasks/main.yml b/ansible/roles/ssh-known-host/tasks/main.yml
index babfcd467..3a2724b4f 100644
--- a/ansible/roles/ssh-known-host/tasks/main.yml
+++ b/ansible/roles/ssh-known-host/tasks/main.yml
@@ -1,4 +1,18 @@
 ---
+# If no IP address has been configured for the host on the admin network, this
+# is typically the first task to fail. Provide a friendly message with
+# information on how to resolve the issue.
+- name: Validate SSH address
+  fail:
+    msg: >-
+      Host {{ inventory_hostname }} has no address configured on the admin
+      network. IP addresses may be manually configured in
+      'network-allocations.yml', or are automatically allocated during the
+      following commands: 'kayobe seed hypervisor host configure', 'kayobe
+      seed host configure', 'kayobe overcloud host configure', 'kayobe seed
+      vm provision' and 'kayobe overcloud inventory discover'.
+  when: not ansible_host | default(inventory_hostname)
+
 - name: Scan for SSH keys
   local_action:
     module: command ssh-keyscan {{ item }}
diff --git a/releasenotes/notes/improve-ssh-known-host-error-15fbc6ae4fa3dbd6.yaml b/releasenotes/notes/improve-ssh-known-host-error-15fbc6ae4fa3dbd6.yaml
new file mode 100644
index 000000000..58a6e9c08
--- /dev/null
+++ b/releasenotes/notes/improve-ssh-known-host-error-15fbc6ae4fa3dbd6.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Improves error message seen when discovering SSH known hosts for a host
+    without an IP address defined in
+    ``${KAYOBE_CONFIG_PATH}/network-allocation.yml``.