I am using the EC2 API to add/update SlaveTemplates.

It seems the cloud.addTemplate() function forgets to set the "parent" field in the new template.

In turn an exception is thrown when trying to provision a new node based on that template.

 
13:19:12 Also: org.jenkinsci.plugins.workflow.actions.ErrorAction$ErrorId: a700b4b5-d1e3-413c-9d91-7aa07891c7aa*13:19:12* Also: Also: org.jenkinsci.plugins.workflow.actions.ErrorAction$ErrorId: 6ac176d9-ade3-41eb-9f8a-148a0e749a92*13:19:12* java.lang.NullPointerException: Cannot invoke "hudson.plugins.ec2.EC2Cloud.connect()" because the return value of "hudson.plugins.ec2.SlaveTemplate.getParent()" is null*13:19:12* java.lang.NullPointerException: Cannot invoke "hudson.plugins.ec2.EC2Cloud.connect()" because the return value of "hudson.plugins.ec2.SlaveTemplate.getParent()" is null*13:19:12* at hudson.plugins.ec2.SlaveTemplate.getImage(SlaveTemplate.java:1380)13:19:12 at hudson.plugins.ec2.SlaveTemplate.provision(SlaveTemplate.java:932)13:19:12 at hudson.plugins.ec2.EC2Cloud.getNewOrExistingAvailableSlave(EC2Cloud.java:728)13:19:12 at hudson.plugins.ec2.EC2Cloud.provision(EC2Cloud.java:817)13:19:12 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)13:19:12 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)13:19:12 at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)13:19:12 at java.base/java.lang.reflect.Method.invoke(Method.java:569)13:19:12 at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)13:19:12 at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)13:19:12 at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1225)13:19:12 at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)13:19:12 at org.codehaus.groovy.runtime.callsite.PojoMetaClassSite.call(PojoMetaClassSite.java:46)13:19:12 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)13:19:12 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)13:19:12 at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:180)13:19:12 at org.kohsuke.groovy.sandbox.GroovyInterceptor.onMethodCall(GroovyInterceptor.java:23)13:19:12 at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onMethodCall(SandboxInterceptor.java:163)13:19:12 at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:178)13:19:12 at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:182)13:19:12 at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.methodCall(SandboxInvoker.java:17)13:19:12 at org.jenkinsci.plugins.workflow.cps.LoggingInvoker.methodCall(LoggingInvoker.java:105)13:19:12 at WorkflowScript.run(WorkflowScript:162)
 

Please see below code for reference:

def test_tmpl_name = "${target_ami_base_name}-test-worker";
def test_tmpl = findWorkerTemplate(test_tmpl_name);

if(test_tmpl == null)
{{{}}
    println("creating new ${test_tmpl_name} with ${new_ami}");
    test_tmpl = new hudson.plugins.ec2.SlaveTemplate(
        (String)new_ami,                    // String ami,
        reference_tmpl.zone,                // String zone,
        (SpotConfiguration)reference_tmpl.spotConfig,        // SpotConfiguration spotConfig,
        reference_tmpl.securityGroups,        // String securityGroups,
        reference_tmpl.remoteFS,            // String remoteFS,
        reference_tmpl.type,                // com.amazonaws.services.ec2.model.InstanceType type,
        reference_tmpl.ebsOptimized,        // boolean ebsOptimized,
        (String)test_tmpl_name,                // String labelString,
        reference_tmpl.mode,                // Node.Mode mode,
        (String)test_tmpl_name,                // String description,
        reference_tmpl.initScript,            // String initScript,
        reference_tmpl.tmpDir,                // String tmpDir,
        reference_tmpl.userData,            // String userData,
        "1",                                // String numExecutors,
        reference_tmpl.remoteAdmin,            // String remoteAdmin,
        (AMITypeData)reference_tmpl.amiType,// AMITypeData amiType,
        reference_tmpl.javaPath,            // String javaPath,
        reference_tmpl.jvmopts,                // String jvmopts,
        reference_tmpl.stopOnTerminate,        // boolean stopOnTerminate,
        reference_tmpl.subnetId,            // String subnetId,
        (List<EC2Tag>)reference_tmpl.tags,    // List<EC2Tag> tags,
        "5",                                // String idleTerminationMinutes,
        0,                                    // int minimumNumberOfInstances,
        0,                                    // int minimumNumberOfSpareInstances,
        "1",                                // String instanceCapStr,
        reference_tmpl.iamInstanceProfile,    // String iamInstanceProfile,
        true,                                // boolean deleteRootOnTermination,
        reference_tmpl.useEphemeralDevices,    // boolean useEphemeralDevices,
        reference_tmpl.launchTimeoutStr,    // String launchTimeoutStr,
        reference_tmpl.associatePublicIp,    // boolean associatePublicIp,
        reference_tmpl.customDeviceMapping,    // String customDeviceMapping,
        reference_tmpl.connectBySSHProcess,    // boolean connectBySSHProcess,
        reference_tmpl.monitoring,            // boolean monitoring,
        reference_tmpl.t2Unlimited,            // boolean t2Unlimited,
        reference_tmpl.connectionStrategy,    // ConnectionStrategy connectionStrategy,
        1,                                    // int maxTotalUses,
        (List<? extends NodeProperty<?>>)reference_tmpl.nodeProperties,        // List<? extends NodeProperty<?>> nodeProperties
        reference_tmpl.hostKeyVerificationStrategy,    // HostKeyVerificationStrategyEnum hostKeyVerificationStrategy,
        reference_tmpl.tenancy,                    // Tenancy tenancy,
        reference_tmpl.ebsEncryptRootVolume,    // EbsEncryptRootVolume ebsEncryptRootVolume,
        reference_tmpl.metadataEndpointEnabled,    // Boolean ebsEncryptRootVolume,
        reference_tmpl.metadataTokensRequired,    // Boolean metadataTokensRequired,
        reference_tmpl.metadataHopsLimit,        // Integer metadataHopsLimit,
        true                                    // Boolean metdataSupported
    );
    cloud.addTemplate(test_tmpl);
}
else
{{{}}
    println("updating existing ${test_tmpl_name} from ${test_tmpl.ami} to ${new_ami}");
    test_tmpl.ami = new_ami;
}

println("using template ${test_tmpl.description}");
cloud.provision(test_tmpl, 1);