From ddbc8f504678d77612c7b920e35fafc1ee2f8441 Mon Sep 17 00:00:00 2001
From: Glenn Sarti <glennsarti@users.noreply.github.com>
Date: Fri, 3 Mar 2017 17:17:01 -0800
Subject: [PATCH] (POOLER-50) Remove VM migration code

The migrate_vm code introduced in commit 705e5d26d87a3e29a9483bf7 caused errors
and has since been found to be problematic.  This commit removes the changes
introduced as part of PR 167 that peratin to the migrate_vm code.
---
 lib/vmpooler/api/v1.rb         |   1 -
 lib/vmpooler/pool_manager.rb   |  85 ---------
 lib/vmpooler/vsphere_helper.rb |  81 ---------
 spec/helpers.rb                |  11 --
 spec/unit/pool_manager_spec.rb | 322 +--------------------------------
 vmpooler.yaml.example          |   7 -
 6 files changed, 2 insertions(+), 505 deletions(-)

diff --git a/lib/vmpooler/api/v1.rb b/lib/vmpooler/api/v1.rb
index 22a0ef1..3c8c8aa 100644
--- a/lib/vmpooler/api/v1.rb
+++ b/lib/vmpooler/api/v1.rb
@@ -55,7 +55,6 @@ module Vmpooler
 
     def account_for_starting_vm(template, vm)
       backend.sadd('vmpooler__running__' + template, vm)
-      backend.sadd('vmpooler__migrating__' + template, vm)
       backend.hset('vmpooler__active__' + template, vm, Time.now)
       backend.hset('vmpooler__vm__' + vm, 'checkout', Time.now)
 
diff --git a/lib/vmpooler/pool_manager.rb b/lib/vmpooler/pool_manager.rb
index 52f6d61..7e3b246 100644
--- a/lib/vmpooler/pool_manager.rb
+++ b/lib/vmpooler/pool_manager.rb
@@ -498,77 +498,6 @@ module Vmpooler
       end
     end
 
-    def migration_limit(migration_limit)
-      # Returns migration_limit setting when enabled
-      return false if migration_limit == 0 || ! migration_limit
-      migration_limit if migration_limit >= 1
-    end
-
-    def migrate_vm(vm, pool, vsphere)
-      Thread.new do
-        _migrate_vm(vm, pool, vsphere)
-      end
-    end
-
-    def _migrate_vm(vm, pool, vsphere)
-      begin
-        $redis.srem('vmpooler__migrating__' + pool, vm)
-        vm_object = vsphere.find_vm(vm)
-        parent_host, parent_host_name = get_vm_host_info(vm_object)
-        migration_limit = migration_limit $config[:config]['migration_limit']
-        migration_count = $redis.scard('vmpooler__migration')
-
-        if ! migration_limit
-          $logger.log('s', "[ ] [#{pool}] '#{vm}' is running on #{parent_host_name}")
-          return
-        else
-          if migration_count >= migration_limit
-            $logger.log('s', "[ ] [#{pool}] '#{vm}' is running on #{parent_host_name}. No migration will be evaluated since the migration_limit has been reached")
-            return
-          else
-            $redis.sadd('vmpooler__migration', vm)
-            host, host_name = vsphere.find_least_used_compatible_host(vm_object)
-            if host == parent_host
-              $logger.log('s', "[ ] [#{pool}] No migration required for '#{vm}' running on #{parent_host_name}")
-            else
-              finish = migrate_vm_and_record_timing(vm_object, vm, pool, host, parent_host_name, host_name, vsphere)
-              $logger.log('s', "[>] [#{pool}] '#{vm}' migrated from #{parent_host_name} to #{host_name} in #{finish} seconds")
-            end
-            remove_vmpooler_migration_vm(pool, vm)
-          end
-        end
-      rescue => err
-        $logger.log('s', "[x] [#{pool}] '#{vm}' migration failed with an error: #{err}")
-        remove_vmpooler_migration_vm(pool, vm)
-      end
-    end
-
-    def get_vm_host_info(vm_object)
-      parent_host = vm_object.summary.runtime.host
-      [parent_host, parent_host.name]
-    end
-
-    def remove_vmpooler_migration_vm(pool, vm)
-      begin
-        $redis.srem('vmpooler__migration', vm)
-      rescue => err
-        $logger.log('s', "[x] [#{pool}] '#{vm}' removal from vmpooler__migration failed with an error: #{err}")
-      end
-    end
-
-    def migrate_vm_and_record_timing(vm_object, vm_name, pool, host, source_host_name, dest_host_name, vsphere)
-      start = Time.now
-      vsphere.migrate_vm_host(vm_object, host)
-      finish = '%.2f' % (Time.now - start)
-      $metrics.timing("migrate.#{pool}", finish)
-      $metrics.increment("migrate_from.#{source_host_name}")
-      $metrics.increment("migrate_to.#{dest_host_name}")
-      checkout_to_migration = '%.2f' % (Time.now - Time.parse($redis.hget("vmpooler__vm__#{vm_name}", 'checkout')))
-      $redis.hset("vmpooler__vm__#{vm_name}", 'migration_time', finish)
-      $redis.hset("vmpooler__vm__#{vm_name}", 'checkout_to_migration', checkout_to_migration)
-      finish
-    end
-
     def check_pool(pool,maxloop = 0, loop_delay = 5)
       $logger.log('d', "[*] [#{pool['name']}] starting worker thread")
 
@@ -601,7 +530,6 @@ module Vmpooler
             (! $redis.sismember('vmpooler__pending__' + pool['name'], vm['name'])) &&
             (! $redis.sismember('vmpooler__completed__' + pool['name'], vm['name'])) &&
             (! $redis.sismember('vmpooler__discovered__' + pool['name'], vm['name'])) &&
-            (! $redis.sismember('vmpooler__migrating__' + pool['name'], vm['name']))
 
             $redis.sadd('vmpooler__discovered__' + pool['name'], vm['name'])
 
@@ -688,17 +616,6 @@ module Vmpooler
         $logger.log('d', "[!] [#{pool['name']}] _check_pool failed with an error while evaluating discovered VMs: #{err}")
       end
 
-      # MIGRATIONS
-      $redis.smembers("vmpooler__migrating__#{pool['name']}").each do |vm|
-        if inventory[vm]
-          begin
-            migrate_vm(vm, pool['name'], vsphere)
-          rescue => err
-            $logger.log('s', "[x] [#{pool['name']}] '#{vm}' failed to migrate: #{err}")
-          end
-        end
-      end
-
       # REPOPULATE
       ready = $redis.scard("vmpooler__ready__#{pool['name']}")
       total = $redis.scard("vmpooler__pending__#{pool['name']}") + ready
@@ -741,8 +658,6 @@ module Vmpooler
 
       # Clear out the tasks manager, as we don't know about any tasks at this point
       $redis.set('vmpooler__tasks__clone', 0)
-      # Clear out vmpooler__migrations since stale entries may be left after a restart
-      $redis.del('vmpooler__migration')
 
       loop_count = 1
       loop do
diff --git a/lib/vmpooler/vsphere_helper.rb b/lib/vmpooler/vsphere_helper.rb
index cc93250..747cbf9 100644
--- a/lib/vmpooler/vsphere_helper.rb
+++ b/lib/vmpooler/vsphere_helper.rb
@@ -190,87 +190,11 @@ module Vmpooler
       base
     end
 
-    # Returns an array containing cumulative CPU and memory utilization of a host, and its object reference
-    # Params:
-    # +model+:: CPU arch version to match on
-    # +limit+:: Hard limit for CPU or memory utilization beyond which a host is excluded for deployments
-    def get_host_utilization(host, model=nil, limit=90)
-      if model
-        return nil unless host_has_cpu_model? host, model
-      end
-      return nil if host.runtime.inMaintenanceMode
-      return nil unless host.overallStatus == 'green'
-
-      cpu_utilization = cpu_utilization_for host
-      memory_utilization = memory_utilization_for host
-
-      return nil if cpu_utilization > limit
-      return nil if memory_utilization > limit
-
-      [ cpu_utilization + memory_utilization, host ]
-    end
-
-    def host_has_cpu_model?(host, model)
-       get_host_cpu_arch_version(host) == model
-    end
-
-    def get_host_cpu_arch_version(host)
-      cpu_model = host.hardware.cpuPkg[0].description
-      cpu_model_parts = cpu_model.split()
-      arch_version = cpu_model_parts[4]
-      arch_version
-    end
-
-    def cpu_utilization_for(host)
-      cpu_usage = host.summary.quickStats.overallCpuUsage
-      cpu_size = host.summary.hardware.cpuMhz * host.summary.hardware.numCpuCores
-      (cpu_usage.to_f / cpu_size.to_f) * 100
-    end
-
-    def memory_utilization_for(host)
-      memory_usage = host.summary.quickStats.overallMemoryUsage
-      memory_size = host.summary.hardware.memorySize / 1024 / 1024
-      (memory_usage.to_f / memory_size.to_f) * 100
-    end
-
-    def find_least_used_host(cluster)
-      ensure_connected @connection, $credentials
-
-      cluster_object = find_cluster(cluster)
-      target_hosts = get_cluster_host_utilization(cluster_object)
-      least_used_host = target_hosts.sort[0][1]
-      least_used_host
-    end
-
     def find_cluster(cluster)
       datacenter = @connection.serviceInstance.find_datacenter
       datacenter.hostFolder.children.find { |cluster_object| cluster_object.name == cluster }
     end
 
-    def get_cluster_host_utilization(cluster)
-      cluster_hosts = []
-      cluster.host.each do |host|
-        host_usage = get_host_utilization(host)
-        cluster_hosts << host_usage if host_usage
-      end
-      cluster_hosts
-    end
-
-    def find_least_used_compatible_host(vm)
-      ensure_connected @connection, $credentials
-
-      source_host = vm.summary.runtime.host
-      model = get_host_cpu_arch_version(source_host)
-      cluster = source_host.parent
-      target_hosts = []
-      cluster.host.each do |host|
-        host_usage = get_host_utilization(host, model)
-        target_hosts << host_usage if host_usage
-      end
-      target_host = target_hosts.sort[0][1]
-      [target_host, target_host.name]
-    end
-
     def find_pool(poolname)
       ensure_connected @connection, $credentials
 
@@ -405,11 +329,6 @@ module Vmpooler
       snapshot
     end
 
-    def migrate_vm_host(vm, host)
-      relospec = RbVmomi::VIM.VirtualMachineRelocateSpec(host: host)
-      vm.RelocateVM_Task(spec: relospec).wait_for_completion
-    end
-
     def close
       @connection.close
     end
diff --git a/spec/helpers.rb b/spec/helpers.rb
index 7fda0d9..cb69cbf 100644
--- a/spec/helpers.rb
+++ b/spec/helpers.rb
@@ -90,17 +90,6 @@ def create_discovered_vm(name, pool, redis_handle = nil)
   redis_db.sadd("vmpooler__discovered__#{pool}", name)
 end
 
-def create_migrating_vm(name, pool, redis_handle = nil)
-  redis_db = redis_handle ? redis_handle : redis
-  redis_db.hset("vmpooler__vm__#{name}", 'checkout', Time.now)
-  redis_db.sadd("vmpooler__migrating__#{pool}", name)
-end
-
-def add_vm_to_migration_set(name, redis_handle = nil)
-  redis_db = redis_handle ? redis_handle : redis
-  redis_db.sadd('vmpooler__migration', name)
-end
-
 def fetch_vm(vm)
   redis.hgetall("vmpooler__vm__#{vm}")
 end
diff --git a/spec/unit/pool_manager_spec.rb b/spec/unit/pool_manager_spec.rb
index 0c2a619..28df9f6 100644
--- a/spec/unit/pool_manager_spec.rb
+++ b/spec/unit/pool_manager_spec.rb
@@ -1461,216 +1461,6 @@ EOT
     end
   end
 
-
-  describe '#migration_limit' do
-    # This is a little confusing.  Is this supposed to return a boolean
-    # or integer type?
-    [false,0].each do |testvalue|
-      it "should return false for an input of #{testvalue}" do
-        expect(subject.migration_limit(testvalue)).to eq(false)
-      end
-    end
-
-    [1,32768].each do |testvalue|
-      it "should return #{testvalue} for an input of #{testvalue}" do
-        expect(subject.migration_limit(testvalue)).to eq(testvalue)
-      end
-    end
-
-    [-1,-32768].each do |testvalue|
-      it "should return nil for an input of #{testvalue}" do
-        expect(subject.migration_limit(testvalue)).to be_nil
-      end
-    end
-  end
-
-  describe '#migrate_vm' do
-    let(:vsphere) { double('vsphere') }
-
-    before do
-      expect(subject).not_to be_nil
-    end
-
-    it 'calls _migrate_vm' do
-      expect(Thread).to receive(:new).and_yield
-      expect(subject).to receive(:_migrate_vm).with(vm, pool, vsphere)
-
-      subject.migrate_vm(vm, pool, vsphere)
-    end
-  end
-
-  describe "#_migrate_vm" do
-    let(:vsphere) { double('vsphere') }
-    let(:vm_parent_hostname) { 'parent1' }
-    let(:config) {
-      YAML.load(<<-EOT
----
-:config:
-  migration_limit: 5
-:pools:
-  - name: #{pool}
-EOT
-      )
-    }
-
-    before do
-      expect(subject).not_to be_nil
-    end
-
-    context 'when an error occurs' do
-      it 'should log an error message and attempt to remove from vmpooler_migration queue' do
-        expect(vsphere).to receive(:find_vm).with(vm).and_raise(RuntimeError,'MockError')
-        expect(logger).to receive(:log).with('s', "[x] [#{pool}] '#{vm}' migration failed with an error: MockError")
-        expect(subject).to receive(:remove_vmpooler_migration_vm)
-        subject._migrate_vm(vm, pool, vsphere)
-      end
-    end
-
-    context 'when VM does not exist' do
-      it 'should log an error message when VM does not exist' do
-        expect(vsphere).to receive(:find_vm).with(vm).and_return(nil)
-        # This test is quite fragile.  Should refactor the code to make this scenario easier to detect
-        expect(logger).to receive(:log).with('s', "[x] [#{pool}] '#{vm}' migration failed with an error: undefined method `summary' for nil:NilClass")
-        subject._migrate_vm(vm, pool, vsphere)
-      end
-    end
-
-    context 'when VM exists but migration is disabled' do
-      before(:each) do
-        expect(vsphere).to receive(:find_vm).with(vm).and_return(host)
-        allow(subject).to receive(:get_vm_host_info).with(host).and_return([{'name' => vm_parent_hostname}, vm_parent_hostname])
-        create_migrating_vm(vm, pool)
-      end
-
-      [-1,-32768,false,0].each do |testvalue|
-        it "should not migrate a VM if the migration limit is #{testvalue}" do
-          config[:config]['migration_limit'] = testvalue
-          expect(logger).to receive(:log).with('s', "[ ] [#{pool}] '#{vm}' is running on #{vm_parent_hostname}")
-          subject._migrate_vm(vm, pool, vsphere)
-        end
-
-        it "should remove the VM from vmpooler__migrating queue in redis if the migration limit is #{testvalue}" do
-          redis.sadd("vmpooler__migrating__#{pool}", vm)
-          config[:config]['migration_limit'] = testvalue
-
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_truthy
-          subject._migrate_vm(vm, pool, vsphere)
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_falsey
-        end
-      end
-    end
-
-    context 'when VM exists but migration limit is reached' do
-      before(:each) do
-        expect(vsphere).to receive(:find_vm).with(vm).and_return(host)
-        allow(subject).to receive(:get_vm_host_info).with(host).and_return([{'name' => vm_parent_hostname}, vm_parent_hostname])
-
-        create_migrating_vm(vm, pool)
-        redis.sadd('vmpooler__migration', 'fakevm1')
-        redis.sadd('vmpooler__migration', 'fakevm2')
-        redis.sadd('vmpooler__migration', 'fakevm3')
-        redis.sadd('vmpooler__migration', 'fakevm4')
-        redis.sadd('vmpooler__migration', 'fakevm5')
-      end
-
-      it "should not migrate a VM if the migration limit is reached" do
-        expect(logger).to receive(:log).with('s',"[ ] [#{pool}] '#{vm}' is running on #{vm_parent_hostname}. No migration will be evaluated since the migration_limit has been reached")
-        subject._migrate_vm(vm, pool, vsphere)
-      end
-
-      it "should remove the VM from vmpooler__migrating queue in redis if the migration limit is reached" do
-        expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_truthy
-        subject._migrate_vm(vm, pool, vsphere)
-        expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_falsey
-      end
-    end
-
-    context 'when VM exists but migration limit is not yet reached' do
-      before(:each) do
-        expect(vsphere).to receive(:find_vm).with(vm).and_return(host)
-        allow(subject).to receive(:get_vm_host_info).with(host).and_return([{'name' => vm_parent_hostname}, vm_parent_hostname])
-
-        create_migrating_vm(vm, pool)
-        redis.sadd('vmpooler__migration', 'fakevm1')
-        redis.sadd('vmpooler__migration', 'fakevm2')
-      end
-
-      context 'and host to migrate to is the same as the current host' do
-        before(:each) do
-          expect(vsphere).to receive(:find_least_used_compatible_host).with(host).and_return([{'name' => vm_parent_hostname}, vm_parent_hostname])
-        end
-
-        it "should not migrate the VM" do
-          expect(logger).to receive(:log).with('s', "[ ] [#{pool}] No migration required for '#{vm}' running on #{vm_parent_hostname}")
-          subject._migrate_vm(vm, pool, vsphere)
-        end
-
-        it "should remove the VM from vmpooler__migrating queue in redis" do
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_truthy
-          subject._migrate_vm(vm, pool, vsphere)
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_falsey
-        end
-
-        it "should not change the vmpooler_migration queue count" do
-          before_count = redis.scard('vmpooler__migration')
-          subject._migrate_vm(vm, pool, vsphere)
-          expect(redis.scard('vmpooler__migration')).to eq(before_count)
-        end
-
-        it "should call remove_vmpooler_migration_vm" do
-          expect(subject).to receive(:remove_vmpooler_migration_vm)
-          subject._migrate_vm(vm, pool, vsphere)
-        end
-      end
-
-      context 'and host to migrate to different to the current host' do
-        let(:vm_new_hostname) { 'new_hostname' }
-        before(:each) do
-          expect(vsphere).to receive(:find_least_used_compatible_host).with(host).and_return([{'name' => vm_new_hostname}, vm_new_hostname])
-          expect(subject).to receive(:migrate_vm_and_record_timing).with(host, vm, pool, Object, vm_parent_hostname, vm_new_hostname, vsphere).and_return('1.00')
-        end
-
-        it "should migrate the VM" do
-          expect(logger).to receive(:log).with('s', "[>] [#{pool}] '#{vm}' migrated from #{vm_parent_hostname} to #{vm_new_hostname} in 1.00 seconds")
-          subject._migrate_vm(vm, pool, vsphere)
-        end
-
-        it "should remove the VM from vmpooler__migrating queue in redis" do
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_truthy
-          subject._migrate_vm(vm, pool, vsphere)
-          expect(redis.sismember("vmpooler__migrating__#{pool}",vm)).to be_falsey
-        end
-
-        it "should not change the vmpooler_migration queue count" do
-          before_count = redis.scard('vmpooler__migration')
-          subject._migrate_vm(vm, pool, vsphere)
-          expect(redis.scard('vmpooler__migration')).to eq(before_count)
-        end
-
-        it "should call remove_vmpooler_migration_vm" do
-          expect(subject).to receive(:remove_vmpooler_migration_vm)
-          subject._migrate_vm(vm, pool, vsphere)
-        end
-      end
-    end
-  end
-
-  describe "#get_vm_host_info" do
-    before do
-      expect(subject).not_to be_nil
-    end
-
-    let(:vm_object) { double('vm_object') }
-    let(:parent_host) { double('parent_host') }
-
-    it 'should return an array with host information' do
-      expect(vm_object).to receive_message_chain(:summary, :runtime, :host).and_return(parent_host)
-      expect(parent_host).to receive(:name).and_return('vmhostname')
-
-      expect(subject.get_vm_host_info(vm_object)).to eq([parent_host,'vmhostname'])
-    end
-  end
-
   describe "#execute!" do
     let(:threads) {{}}
 
@@ -1703,12 +1493,6 @@ EOT
         expect(redis.get('vmpooler__tasks__clone')).to eq('0')
       end
 
-      it 'should clear migration tasks' do
-        redis.set('vmpooler__migration', 1)
-        subject.execute!(1,0)
-        expect(redis.get('vmpooler__migration')).to be_nil
-      end
-
       it 'should run the check_disk_queue method' do
         expect(subject).to receive(:check_disk_queue)
 
@@ -1965,69 +1749,6 @@ EOT
     end
   end
 
-  describe '#remove_vmpooler_migration_vm' do
-    before do
-      expect(subject).not_to be_nil
-    end
-
-    it 'should remove the migration from redis' do
-      redis.sadd('vmpooler__migration', vm)
-      expect(redis.sismember('vmpooler__migration',vm)).to be(true)
-      subject.remove_vmpooler_migration_vm(pool, vm)
-      expect(redis.sismember('vmpooler__migration',vm)).to be(false)
-    end
-
-    it 'should log a message and swallow an error if one occurs' do
-      expect(redis).to receive(:srem).and_raise(RuntimeError,'MockError')
-      expect(logger).to receive(:log).with('s', "[x] [#{pool}] '#{vm}' removal from vmpooler__migration failed with an error: MockError")
-      subject.remove_vmpooler_migration_vm(pool, vm)
-    end
-  end
-
-  describe '#migrate_vm_and_record_timing' do
-    let(:vsphere) { double('vsphere') }
-    let(:vm_object) { double('vm_object') }
-    let(:source_host_name) { 'source_host' }
-    let(:dest_host_name) { 'dest_host' }
-
-    before do
-      expect(subject).not_to be_nil
-    end
-
-    before(:each) do
-      create_vm(vm,token)
-      expect(vsphere).to receive(:migrate_vm_host).with(vm_object, host)
-    end
-
-    it 'should return the elapsed time for the migration' do
-      result = subject.migrate_vm_and_record_timing(vm_object, vm, pool, host, source_host_name, dest_host_name, vsphere)
-      expect(result).to match(/0\.[\d]+/)
-    end
-
-    it 'should add timing metric' do
-      expect(metrics).to receive(:timing).with("migrate.#{pool}",String)
-      subject.migrate_vm_and_record_timing(vm_object, vm, pool, host, source_host_name, dest_host_name, vsphere)
-    end
-
-    it 'should increment from_host and to_host metric' do
-      expect(metrics).to receive(:increment).with("migrate_from.#{source_host_name}")
-      expect(metrics).to receive(:increment).with("migrate_to.#{dest_host_name}")
-      subject.migrate_vm_and_record_timing(vm_object, vm, pool, host, source_host_name, dest_host_name, vsphere)
-    end
-
-    it 'should set migration_time metric in redis' do
-      expect(redis.hget("vmpooler__vm__#{vm}", 'migration_time')).to be_nil
-      subject.migrate_vm_and_record_timing(vm_object, vm, pool, host, source_host_name, dest_host_name, vsphere)
-      expect(redis.hget("vmpooler__vm__#{vm}", 'migration_time')).to match(/0\.[\d]+/)
-    end
-
-    it 'should set checkout_to_migration metric in redis' do
-      expect(redis.hget("vmpooler__vm__#{vm}", 'checkout_to_migration')).to be_nil
-      subject.migrate_vm_and_record_timing(vm_object, vm, pool, host, source_host_name, dest_host_name, vsphere)
-      expect(redis.hget("vmpooler__vm__#{vm}", 'checkout_to_migration')).to match(/0\.[\d]+/)
-    end
-  end
-
   describe '#_check_pool' do
     # Default test fixtures will consist of;
     #   - Empty Redis dataset
@@ -2057,7 +1778,6 @@ EOT
     # INVENTORY
     context 'Conducting inventory' do
       before(:each) do
-        allow(subject).to receive(:migrate_vm)
         allow(subject).to receive(:check_running_vm)
         allow(subject).to receive(:check_ready_vm)
         allow(subject).to receive(:check_pending_vm)
@@ -2092,7 +1812,7 @@ EOT
         expect(redis.sismember("vmpooler__completed__#{pool}", new_vm)).to be(true)
       end
 
-      ['running','ready','pending','completed','discovered','migrating'].each do |queue_name|
+      ['running','ready','pending','completed','discovered'].each do |queue_name|
         it "should not discover VMs in the #{queue_name} queue" do
           expect(vsphere).to receive(:find_folder).and_return(MockFindFolder.new([new_vm]))
 
@@ -2356,7 +2076,6 @@ EOT
       ['pending','ready','running','completed'].each do |queue_name|
         context "exists in the #{queue_name} queue" do
           before(:each) do
-            allow(subject).to receive(:migrate_vm)
             allow(subject).to receive(:check_running_vm)
             allow(subject).to receive(:check_ready_vm)
             allow(subject).to receive(:check_pending_vm)
@@ -2392,43 +2111,6 @@ EOT
       end
     end
 
-    # MIGRATIONS
-    context 'Migrating VM not in the inventory' do
-      before(:each) do
-        expect(vsphere).to receive(:find_folder).and_return(MockFindFolder.new([new_vm]))
-        expect(logger).to receive(:log).with('s', "[?] [#{pool}] '#{new_vm}' added to 'discovered' queue")
-        create_migrating_vm(vm,pool)
-      end
-
-      it 'should not do anything' do
-        expect(subject).to receive(:migrate_vm).exactly(0).times
-
-        subject._check_pool(pool_object,vsphere)
-      end
-    end
-
-    context 'Migrating VM in the inventory' do
-      before(:each) do
-        expect(vsphere).to receive(:find_folder).and_return(MockFindFolder.new([vm]))
-        allow(subject).to receive(:check_ready_vm)
-        allow(logger).to receive(:log).with("s", "[!] [#{pool}] is empty")
-        create_migrating_vm(vm,pool)
-      end
-
-      it 'should log an error if one occurs' do
-        expect(subject).to receive(:migrate_vm).and_raise(RuntimeError,'MockError')
-        expect(logger).to receive(:log).with('s', "[x] [#{pool}] '#{vm}' failed to migrate: MockError")
-
-        subject._check_pool(pool_object,vsphere)
-      end
-
-      it 'should call migrate_vm' do
-        expect(subject).to receive(:migrate_vm).with(vm,pool,vsphere)
-
-        subject._check_pool(pool_object,vsphere)
-      end
-    end
-
     # REPOPULATE
     context 'Repopulate a pool' do
       it 'should not call clone_vm when number of VMs is equal to the pool size' do
@@ -2458,7 +2140,7 @@ EOT
         end
       end
 
-      ['running','completed','discovered','migrating'].each do |queue_name|
+      ['running','completed','discovered'].each do |queue_name|
         it "should not use VMs in #{queue_name} queue to caculate pool size" do
           expect(vsphere).to receive(:find_folder).and_return(MockFindFolder.new([vm]))
           expect(subject).to receive(:clone_vm)
diff --git a/vmpooler.yaml.example b/vmpooler.yaml.example
index c128b5d..a2c9fd0 100644
--- a/vmpooler.yaml.example
+++ b/vmpooler.yaml.example
@@ -247,13 +247,6 @@
 #     a separator.
 #     (optional; default: '')
 #
-#   - migration_limit
-#     When set to any value greater than 0 enable VM migration at checkout.
-#     When enabled this capability will evaluate a VM for migration when it is requested
-#     in an effort to maintain a more even distribution of load across compute resources.
-#     The migration_limit ensures that no more than n migrations will be evaluated at any one time
-#     and greatly reduces the possibilty of VMs ending up bunched together on a particular host.
-#
 #  - max_tries
 #    Set the max number of times a connection should retry in vsphere helper.
 #    This optional setting allows a user to dial in retry limits to