(PE-40375) - Phase 1 - Pre-migration checks (#558)

* Do the hostnames exist - if yes can they be connected to
* does a replica host exist - if yes can it be connected to
* is a valid PE version used - if it's being upgraded is the upgraded version valid
* is original cluster operational, is it a supported PE architecture

---------

Co-authored-by: David Mallon <[email protected]>

Author: B00885424

plans/migrate.pp

@@ -9,14 +9,41 @@
 # @param upgrade_version
 #   Optional version to upgrade to after migration is complete
 #
+#
 plan peadm::migrate (
   Peadm::SingleTargetSpec $old_primary_host,
   Peadm::SingleTargetSpec $new_primary_host,
   Optional[String] $upgrade_version = undef,
   Optional[Peadm::SingleTargetSpec] $replica_host = undef,
 ) {
+  # pre-migration checks
   out::message('This plan is a work in progress and it is not recommended to be used until it is fully implemented and supported')
   peadm::assert_supported_bolt_version()
+  if $upgrade_version and $upgrade_version != '' and !empty($upgrade_version) {
+    $permit_unsafe_versions = false
+    peadm::assert_supported_pe_version($upgrade_version, $permit_unsafe_versions)
+  }
+
+  $all_hosts = peadm::flatten_compact([
+    $old_primary_host,
+    $new_primary_host,
+    $replica_host ? { undef => [], default => [$replica_host] }
+  ].flatten)
+  run_command('hostname', $all_hosts)  # verify can connect to targets
+
+  # verify the cluster we are migrating from is operational and is a supported architecture
+  $cluster = run_task('peadm::get_peadm_config', $old_primary_host).first.value
+  $error = getvar('cluster.error')
+  if $error {
+    fail_plan($error)
+  }
+  $arch = peadm::assert_supported_architecture(
+    getvar('cluster.params.primary_host'),
+    getvar('cluster.params.replica_host'),
+    getvar('cluster.params.primary_postgresql_host'),
+    getvar('cluster.params.replica_postgresql_host'),
+    getvar('cluster.params.compiler_hosts'),
+  )
 
   $backup_file = run_plan('peadm::backup', $old_primary_host, {
       backup_type => 'migration',