Kubernetes error building cluster, utility subnet can't be found - kubernetes

Question

Why is it that when I try to update a new Kubernetes cluster it gives the following error:
$ kops update cluster --name k8s-web-dev
error building tasks: could not find utility subnet in zone: "us-east-1b"
I have not been able to deploy it into aws yet. It only creates configs inside s3.
Also because I have private and public subnets I am updating manually k8s config to point to correct subnet-ids. e.g: The ids were added manually.
subnets:
- cidr: 10.0.0.0/19
id: subnet-3724bb40
name: us-east-1b
type: Private
zone: us-east-1b
- cidr: 10.0.64.0/19
id: subnet-918a35c8
name: us-east-1c
type: Private
zone: us-east-1c
- cidr: 10.0.32.0/20
id: subnet-4824bb3f
name: utility-us-east-1b
type: Public
zone: us-east-1b
- cidr: 10.0.96.0/20
id: subnet-908a35c9
name: utility-us-east-1c
type: Public
zone: us-east-1c
Also interestingly enough I did no change in my config. But when I run the kops update once and then once more I get two different results. How is that possible?
kops update cluster --name $n
error building tasks: could not find utility subnet in zone: "us-east-1c"
and then this
kops update cluster --name $n
error building tasks: could not find utility subnet in zone: "us-east-1b"

Answer 1

Using --bastion parameter within kops command line options assumes that bastion instance group is already in place. To create bastion instance group you can use --role flag:
kops create instancegroup bastions --role Bastion --subnet $SUBNET
Check this link for more information.