Hello Shruthi,

Even I too faced this issue, but this got fixed after upgrading the Jenkins to 2.235.3 version.

Thanks,

I too faced the same issue, even after upgrading Jenkins to 2.235.3 version.
Starting Kubernetes deployment
Loading configuration: /var/lib/jenkins/workspace/demo/deploy.yml
ERROR: ERROR: Can't construct a java object for tag:yaml.org,2002:io.kubernetes.client.openapi.models.V1ConfigMap; exception=Class not found: io.kubernetes.client.openapi.models.V1ConfigMap
in 'reader', line 1, column 1:
apiVersion: v1
^

hudson.remoting.ProxyException: Can't construct a java object for tag:yaml.org,2002:io.kubernetes.client.openapi.models.V1ConfigMap; exception=Class not found: io.kubernetes.client.openapi.models.V1ConfigMap
in 'reader', line 1, column 1:
apiVersion: v1
^

at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.construct(Constructor.java:336)
at org.yaml.snakeyaml.constructor.BaseConstructor.constructObjectNoCheck(BaseConstructor.java:230)
at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:219)
at io.kubernetes.client.util.Yaml$CustomConstructor.constructObject(Yaml.java:337)
at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:173)
at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:157)
at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:472)
at org.yaml.snakeyaml.Yaml.loadAs(Yaml.java:438)
at io.kubernetes.client.util.Yaml.loadAs(Yaml.java:224)
at io.kubernetes.client.util.Yaml.modelMapper(Yaml.java:494)
at io.kubernetes.client.util.Yaml.loadAll(Yaml.java:272)
at com.microsoft.jenkins.kubernetes.wrapper.KubernetesClientWrapper.apply(KubernetesClientWrapper.java:236)
at com.microsoft.jenkins.kubernetes.command.DeploymentCommand$DeploymentTask.doCall(DeploymentCommand.java:172)
at com.microsoft.jenkins.kubernetes.command.DeploymentCommand$DeploymentTask.call(DeploymentCommand.java:124)
at com.microsoft.jenkins.kubernetes.command.DeploymentCommand$DeploymentTask.call(DeploymentCommand.java:106)
at hudson.FilePath.act(FilePath.java:1162)
at com.microsoft.jenkins.kubernetes.command.DeploymentCommand.execute(DeploymentCommand.java:68)
at com.microsoft.jenkins.kubernetes.command.DeploymentCommand.execute(DeploymentCommand.java:45)
at com.microsoft.jenkins.azurecommons.command.CommandService.runCommand(CommandService.java:88)
at com.microsoft.jenkins.azurecommons.command.CommandService.execute(CommandService.java:96)
at com.microsoft.jenkins.azurecommons.command.CommandService.executeCommands(CommandService.java:75)
at com.microsoft.jenkins.azurecommons.command.BaseCommandContext.executeCommands(BaseCommandContext.java:77)
at com.microsoft.jenkins.kubernetes.KubernetesDeploy.perform(KubernetesDeploy.java:42)
at com.microsoft.jenkins.azurecommons.command.SimpleBuildStepExecution.run(SimpleBuildStepExecution.java:54)
at com.microsoft.jenkins.azurecommons.command.SimpleBuildStepExecution.run(SimpleBuildStepExecution.java:35)
at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: hudson.remoting.ProxyException: org.yaml.snakeyaml.error.YAMLException: Class not found: io.kubernetes.client.openapi.models.V1ConfigMap
at org.yaml.snakeyaml.constructor.Constructor.getClassForNode(Constructor.java:664)
at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.getConstructor(Constructor.java:322)
at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.construct(Constructor.java:331)
... 30 more[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] }[Pipeline] // withEnv[Pipeline] }[Pipeline] // node[Pipeline] End of PipelineERROR: Kubernetes deployment ended with HasError
Finished: FAILURE

Hi , This issue seems to be with the update of jackson2-api-plugin from 2.10 to 2.11 . 

https://issues.jenkins-ci.org/browse/JENKINS-62995

Logs:
[Pipeline]

I have found the solution to this problem. I have tried many times and it's working perfectly. Kubernetes CD plugin should be Version 1.0. No need to downgrade other plugins.

Kindly hit this [link|https://updates.jenkins.io/download/plugins/kubernetes-cd/1.0.0/kubernetes-cd.hpi] to download the version 1.0.0 .hpi file of the Kubernetes cd plugin from the official Jenkins plugin site.

Reference - https://plugins.jenkins.io/kubernetes-cd/#releases