fix: capture stderr in execCapture and let iptables MSS failures propagate

Author: jshi991

Sources/ContainerK8s/K8sHelper.swift

@@ -199,7 +199,7 @@ struct K8sHelper {
             executable: executable, arguments: arguments, environment: [], terminal: false)
         let proc = try await client.createProcess(
             containerId: containerId, processId: UUID().uuidString.lowercased(),
-            configuration: config, stdio: [nil, pipe.fileHandleForWriting, nil])
+            configuration: config, stdio: [nil, pipe.fileHandleForWriting, pipe.fileHandleForWriting])
         try await proc.start()
         pipe.fileHandleForWriting.closeFile()
         let data = pipe.fileHandleForReading.readDataToEndOfFile()
@@ -291,8 +291,8 @@ struct K8sHelper {
         sysctl -w net.bridge.bridge-nf-call-ip6tables=1 2>/dev/null || true
         systemctl restart containerd
         ctr -n k8s.io images tag registry.k8s.io/pause:3.10 registry.k8s.io/pause:3.10.1 2>/dev/null || true
-        /usr/sbin/iptables-nft -t mangle -A OUTPUT  -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1220 2>/dev/null || true
-        /usr/sbin/iptables-nft -t mangle -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1220 2>/dev/null || true
+        /usr/sbin/iptables-nft -t mangle -A OUTPUT  -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1220
+        /usr/sbin/iptables-nft -t mangle -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1220
         """
     }()
 

Sources/Plugins/K8s/K8sCommand.swift

@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 import ArgumentParser
+import ContainerK8s
 import ContainerVersion
 
 public struct K8sCommand: AsyncParsableCommand {