<p>I deployed a cluster in AWS 3 AZ, I want to start one master on each AZ. Everything else works except I cannot start one master in one AZ.</p>

<p>Here is my validation:</p>

<pre><code>INSTANCE GROUPS
NAME                    ROLE    MACHINETYPE     MIN     MAX     SUBNETS
bastions                Bastion t2.micro        1       1       utility-us-east-1a,utility-us-east-1c,utility-us-east-1d
master-us-east-1a       Master  m3.medium       1       1       us-east-1a
master-us-east-1c       Master  m3.medium       2       2       us-east-1c
master-us-east-1d       Master  m3.medium       1       1       us-east-1d
nodes                   Node    m4.xlarge       3       3       us-east-1a,us-east-1c,us-east-1d
workers                 Node    m4.2xlarge      2       2       us-east-1a,us-east-1c,us-east-1d

NODE STATUS
NAME                            ROLE    READY
ip-10-0-100-34.ec2.internal     node    True
ip-10-0-107-127.ec2.internal    master  True
ip-10-0-120-160.ec2.internal    node    True
ip-10-0-35-184.ec2.internal     node    True
ip-10-0-39-224.ec2.internal     master  True
ip-10-0-59-109.ec2.internal     node    True
ip-10-0-87-169.ec2.internal     node    True

VALIDATION ERRORS
KIND            NAME                    MESSAGE
InstanceGroup   master-us-east-1c       InstanceGroup "master-us-east-1c" did not have enough nodes 0 vs 2

Validation Failed
</code></pre>

<p>And if I use rolling update, it shows there is one master not started:</p>

<pre><code>NAME                    STATUS  NEEDUPDATE      READY   MIN     MAX     NODES
bastions                Ready   0               1       1       1       0
master-us-east-1a       Ready   0               1       1       1       1
master-us-east-1c       Ready   0               0       1       1       0
master-us-east-1d       Ready   0               1       1       1       1
nodes                   Ready   0               3       3       3       3
workers                 Ready   0               2       2       2       2
</code></pre>

<p>What shall I do to bring that machine up?</p>

Xiang Zhang
<p>I solved this problem. It is because the <code>m3.medium</code> type (the default one in kops for master) is no longer available in that AZ. Change it to <code>m4.large</code> makes it work.</p>
