Parameters: [KeyPair] must have values - amazon-web-services

Question

I am trying to mirror my EC2 instance using cloudformation. Currently, I've been able to create the following JSON using troposphere and I come across the error 'Parameters: [KeyPair] must have values'. I am not sure what this 'values' has to be?
I understand the error but not sure what's the solution.
{
"Outputs": {
"InstanceAccess": {
"Description": "",
"Value": {
"Fn::Join": [
"",
[
"ssh -i ",
{
"Ref": "KeyPair"
},
" ubuntu#",
{
"Fn::GetAtt": [
"MyInstance",
"PublicDnsName"
]
}
]
]
}
}
},
"Parameters": {
"KeyPair": {
"Description": "jj",
"Type": "AWS::EC2::KeyPair::launch"
}
},
"Resources": {
"MyInstance": {
"Properties": {
"ImageId": "< my image id goes here>",
"InstanceType": "t1.micro",
"KeyName": {
"Ref": "KeyPair"
},
"SecurityGroups": [
{
"Ref": "SecurityGroup"
}
]
},
"Type": "AWS::EC2::Instance"
},
"SecurityGroup": {
"Properties": {
"GroupDescription": "Allow access to MyInstance",
"SecurityGroupIngress": [
{
"CidrIp": "0.0.0.0/0",
"FromPort": "22",
"IpProtocol": "tcp",
"ToPort": "22"
},
{
"CidrIp": "0.0.0.0/0",
"FromPort": "80",
"IpProtocol": "tcp",
"ToPort": "80"
},
{
"CidrIp": "0.0.0.0/0",
"FromPort": "8080",
"IpProtocol": "tcp",
"ToPort": "8080"
},
{
"CidrIp": "0.0.0.0/0",
"FromPort": "443",
"IpProtocol": "tcp",
"ToPort": "443"
}
]
},
"Type": "AWS::EC2::SecurityGroup"
}
}
}

Answer 1

Your KeyPair parameter should have a valid type. According to the Parameters section of the CloudFormation User Guide, the type for a KeyPair parameter is AWS::EC2::KeyPair::KeyName. So it should look like this:
"KeyPair": {
"Description": "The name of the keypair to use for SSH access",
"Type": "AWS::EC2::KeyPair::KeyName"
}
Also, if you declare a key pair name as a parameter in your template, you'll have to pass an existing key pair name as an argument when you create a stack using that template.

Answer 2

To expand on the accepted answer, you can add a default value for the parameter. This would have also resolved the error you were seeing. If KeyPair has a static value, you may prefer a default over passing an argument. You can still override the default by passing an argument.
"KeyPair": {
"Description": "The name of the keypair to use for SSH access",
"Type": "AWS::EC2::KeyPair::KeyName",
"Default": "launch"
}