diff --git a/UpdatePod.Domain/ImageOperations/ImageOperationsWithDockerIo.cs b/UpdatePod.Domain/ImageOperations/ImageOperationsWithDockerIo.cs
index 281ae44..6cb169c 100644
--- a/UpdatePod.Domain/ImageOperations/ImageOperationsWithDockerIo.cs
+++ b/UpdatePod.Domain/ImageOperations/ImageOperationsWithDockerIo.cs
@@ -8,7 +8,7 @@ namespace UpdatePod.Domain.ImageOperations;
 public class ImageOperationsWithDockerIo(HttpClient httpClient, ImageOperationData imageOperationData) : IImageOperationsStrategy
 {
     
-    public async Task<string?> GetLatestHash(string repository, string tag, CancellationToken ct = default)
+    public async Task<string?> GetLatestHash(string repository, string tag, CancellationToken token = default)
     {
         httpClient.DefaultRequestHeaders.Add("Accept", "application/json");
 
@@ -18,7 +18,7 @@ public class ImageOperationsWithDockerIo(HttpClient httpClient, ImageOperationDa
         }
         
         var cancellationTokenWithTimeoutCancellation=HttpClientUtils.
-            GenerateCancellationTokenWithTimeout(ct, TimeSpan.FromSeconds(imageOperationData.GetImageOperationsTimeout()));
+            GenerateCancellationTokenWithTimeout(token, TimeSpan.FromSeconds(imageOperationData.GetImageOperationsTimeout()));
         
         var url = GetUrl(repository, tag);
 
diff --git a/UpdatePod.Domain/ImageOperations/ImageOperationsWithHarbor.cs b/UpdatePod.Domain/ImageOperations/ImageOperationsWithHarbor.cs
index 0d30567..c91c4df 100644
--- a/UpdatePod.Domain/ImageOperations/ImageOperationsWithHarbor.cs
+++ b/UpdatePod.Domain/ImageOperations/ImageOperationsWithHarbor.cs
@@ -43,7 +43,7 @@ public class ImageOperationsWithHarbor(HttpClient httpClient, ImageOperationData
         }
 
         var canGetHeader = response.Headers.TryGetValues("docker-content-digest", out var digest);
-        return !canGetHeader ? null : digest?.ToList().FirstOrDefault();
+        return !canGetHeader ? null : digest.FirstOrDefault();
    
         
     }
diff --git a/UpdatePod.Domain/KubernetesUtils/IKubernetesOperations.cs b/UpdatePod.Domain/KubernetesUtils/IKubernetesOperations.cs
index 0233d44..a4f261b 100644
--- a/UpdatePod.Domain/KubernetesUtils/IKubernetesOperations.cs
+++ b/UpdatePod.Domain/KubernetesUtils/IKubernetesOperations.cs
@@ -13,6 +13,6 @@ public interface IKubernetesOperations
     
     public Task<bool> RestartDeployment(string namespaceInfo, string deployment, CancellationToken ct = default);
     
-    public Task<bool> RestartStateFulSet(string namespaceInfo, string deployment, CancellationToken ct = default);
+    public Task<bool> RestartStateFulSet(string namespaceInfo, string statefulSetName, CancellationToken ct = default);
     
 }
\ No newline at end of file
diff --git a/UpdatePod.Domain/KubernetesUtils/KubernetesOperationWithKubernetesClient.cs b/UpdatePod.Domain/KubernetesUtils/KubernetesOperationWithKubernetesClient.cs
index f19c7e0..e3f55c5 100644
--- a/UpdatePod.Domain/KubernetesUtils/KubernetesOperationWithKubernetesClient.cs
+++ b/UpdatePod.Domain/KubernetesUtils/KubernetesOperationWithKubernetesClient.cs
@@ -148,7 +148,7 @@ public async  Task<string> GetStateFulSetFromPod(string namespaceInfo, string po
         
         if (stName is null)
         {
-            throw new Exception(Msg.StatefulSetNotFound(matchedPod.Metadata.Name));
+            throw new KubernetesObjectNotFoundException(Msg.StatefulSetNotFound(matchedPod.Metadata.Name));
         }
         
         return stName;
diff --git a/UpdatePod.Domain/PodUpdateOperations/InvalidImagePullPolicyException.cs b/UpdatePod.Domain/PodUpdateOperations/InvalidImagePullPolicyException.cs
new file mode 100644
index 0000000..877eacb
--- /dev/null
+++ b/UpdatePod.Domain/PodUpdateOperations/InvalidImagePullPolicyException.cs
@@ -0,0 +1,7 @@
+namespace UpdatePod.Domain.PodUpdateOperations;
+
+public class InvalidImagePullPolicyException: Exception
+{
+    public InvalidImagePullPolicyException(string actual, string expected)
+        : base($"Image pull policy must be {expected} but {actual}") {}   
+}
\ No newline at end of file
diff --git a/UpdatePod.Domain/PodUpdateOperations/PodUpdateOperationWithDomain.cs b/UpdatePod.Domain/PodUpdateOperations/PodUpdateOperationWithDomain.cs
index 541d654..27309db 100644
--- a/UpdatePod.Domain/PodUpdateOperations/PodUpdateOperationWithDomain.cs
+++ b/UpdatePod.Domain/PodUpdateOperations/PodUpdateOperationWithDomain.cs
@@ -51,7 +51,7 @@ private static void ValidateImagePullPolicy(string imagePullPolicy)
     {
         if (imagePullPolicy != ImagePullPolicyAlways)
         {
-            throw new ApplicationException($"Image pull policy must be {ImagePullPolicyAlways} but {imagePullPolicy}");
+            throw new InvalidImagePullPolicyException( ImagePullPolicyAlways, imagePullPolicy);
         }
     }
 
@@ -70,7 +70,7 @@ private async Task<string> GetPodContainerImageInfo(string nameSpace, string pod
         return await _imageOperations.GetLatestHashFromImage(containerImageName, cancellationToken);
     }
 
-    private void ValidateLatestImageHash(string? latestImageHashFromRegistry, string? containerName)
+    private static void ValidateLatestImageHash(string? latestImageHashFromRegistry, string? containerName)
     {
         if (latestImageHashFromRegistry is null)
         {
diff --git a/UpdatePod/Worker.cs b/UpdatePod/Worker.cs
index 5233700..37bbdb6 100644
--- a/UpdatePod/Worker.cs
+++ b/UpdatePod/Worker.cs
@@ -30,13 +30,13 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
         }
     }
 
-    private (string nameSpace, string podNameStarts, int intervalMinutes, string? containerName) GetInfoFromEnvironment()
+    private static (string nameSpace, string podNameStarts, int intervalMinutes, string? containerName) GetInfoFromEnvironment()
     {
         var namespaceInfo = Environment.GetEnvironmentVariable("POD_NAMESPACE") 
-                            ?? throw new Exception("POD_NAMESPACE env var is missing.");
+                            ?? throw new ArgumentException("POD_NAMESPACE env var is missing.");
 
         var podNameStarts = Environment.GetEnvironmentVariable("POD_NAME_PREFIX") 
-                            ?? throw new Exception("POD_NAME_PREFIX env var is missing.");
+                            ?? throw new ArgumentException("POD_NAME_PREFIX env var is missing.");
 
         var containerName = Environment.GetEnvironmentVariable("POD_CONTAINER_NAME");