diff --git a/src/exec.c b/src/exec.c
index 96b1c534..5c5998c9 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -590,7 +590,7 @@ static void hyper_free_exec(struct hyper_exec *exec)
 	free(exec);
 }
 
-int hyper_exec_cmd(char *json, int length)
+int hyper_exec_cmd(struct hyper_pod *pod, char *json, int length)
 {
 	struct hyper_exec *exec;
 
@@ -602,7 +602,18 @@ int hyper_exec_cmd(char *json, int length)
 		return -1;
 	}
 
-	exec->pod = &global_pod;
+	if (hyper_find_container(pod, exec->container_id) == NULL) {
+		fprintf(stderr, "call hyper_exec_cmd, no such container: %s\n", exec->container_id);
+		hyper_free_exec(exec);
+		return -1;
+	}
+	if (hyper_find_exec_by_name(pod, exec->id) != NULL) {
+		fprintf(stderr, "call hyper_exec_cmd, process id conflicts");
+		hyper_free_exec(exec);
+		return -1;
+	}
+
+	exec->pod = pod;
 	int ret = hyper_run_process(exec);
 	if (ret < 0) {
 		hyper_free_exec(exec);
@@ -719,6 +730,24 @@ static int hyper_release_exec(struct hyper_exec *exec)
 	return 0;
 }
 
+struct hyper_exec *hyper_find_process(struct hyper_pod *pod, const char *container, const char *process)
+{
+	struct hyper_container *c = hyper_find_container(pod, container);
+	if (c) {
+		if (strcmp(c->exec.id, process) == 0) {
+			return &c->exec;
+		}
+	} else {
+		return NULL;
+	}
+
+	struct hyper_exec *exec = hyper_find_exec_by_name(pod, process);
+	if (strcmp(exec->container_id, container) == 0) {
+		return exec;
+	}
+	return NULL;
+}
+
 struct hyper_exec *hyper_find_exec_by_name(struct hyper_pod *pod, const char *process)
 {
 	struct hyper_exec *exec;
diff --git a/src/exec.h b/src/exec.h
index 09ef1ebe..bad5ca49 100644
--- a/src/exec.h
+++ b/src/exec.h
@@ -44,8 +44,9 @@ struct hyper_exec {
 
 struct hyper_pod;
 
-int hyper_exec_cmd(char *json, int length);
+int hyper_exec_cmd(struct hyper_pod *pod, char *json, int length);
 int hyper_run_process(struct hyper_exec *e);
+struct hyper_exec *hyper_find_process(struct hyper_pod *pod, const char *container, const char *process);
 struct hyper_exec *hyper_find_exec_by_name(struct hyper_pod *pod, const char *process);
 struct hyper_exec *hyper_find_exec_by_pid(struct list_head *head, int pid);
 struct hyper_exec *hyper_find_exec_by_seq(struct hyper_pod *pod, uint64_t seq);
diff --git a/src/hyper.h b/src/hyper.h
index ec67a052..c6e38f96 100644
--- a/src/hyper.h
+++ b/src/hyper.h
@@ -87,7 +87,6 @@ int hyper_enter_sandbox(struct hyper_pod *pod, int pidpipe);
 void hyper_pod_destroyed(int failed);
 int hyper_ctl_append_msg(struct hyper_event *he, uint32_t type, uint8_t *data, uint32_t len);
 
-extern struct hyper_pod global_pod;
 extern struct hyper_epoll hyper_epoll;
 extern sigset_t orig_mask;
 #endif
diff --git a/src/init.c b/src/init.c
index df67fc32..bf5b4ce9 100644
--- a/src/init.c
+++ b/src/init.c
@@ -30,7 +30,7 @@
 #include "container.h"
 #include "syscall.h"
 
-struct hyper_pod global_pod = {
+static struct hyper_pod global_pod = {
 	.containers	=	LIST_HEAD_INIT(global_pod.containers),
 	.exec_head	=	LIST_HEAD_INIT(global_pod.exec_head),
 };
@@ -62,20 +62,11 @@ static int hyper_set_win_size(struct hyper_pod *pod, char *json, int length)
 		goto out;
 	}
 
-	struct hyper_container *c = hyper_find_container(pod, container);
-	if (!c) {
-		fprintf(stderr, "call hyper_set_win_size, can not find the container: %s\n", container);
+	exec = hyper_find_process(pod, container, process);
+	if (!exec) {
+		fprintf(stderr, "call hyper_set_win_size, can not find the process: %s\n", process);
 		goto out;
 	}
-	if (strcmp(c->exec.id, process) == 0) {
-		exec = &c->exec;
-	} else {
-		exec = hyper_find_exec_by_name(pod, process);
-		if (!exec) {
-			fprintf(stderr, "call hyper_set_win_size, can not find the process: %s\n", process);
-			goto out;
-		}
-	}
 
 	size.ws_row = (int)json_object_get_number(json_object(value), "row");
 	size.ws_col = (int)json_object_get_number(json_object(value), "column");
@@ -564,10 +555,8 @@ static int hyper_destroy_pod(struct hyper_pod *pod, int error)
 	return 0;
 }
 
-static int hyper_start_pod(char *json, int length)
+static int hyper_start_pod(struct hyper_pod *pod, char *json, int length)
 {
-	struct hyper_pod *pod = &global_pod;
-
 	fprintf(stdout, "call hyper_start_pod, json %s, len %d\n", json, length);
 
 	if (pod->init_pid)
@@ -593,11 +582,10 @@ static int hyper_start_pod(char *json, int length)
 	return 0;
 }
 
-static int hyper_new_container(char *json, int length)
+static int hyper_new_container(struct hyper_pod *pod, char *json, int length)
 {
 	int ret;
 	struct hyper_container *c;
-	struct hyper_pod *pod = &global_pod;
 
 	fprintf(stdout, "call hyper_new_container, json %s, len %d\n", json, length);
 
@@ -612,6 +600,12 @@ static int hyper_new_container(char *json, int length)
 		return -1;
 	}
 
+	if (hyper_find_container(pod, c->id) != NULL) {
+		fprintf(stderr, "container id conflicts");
+		hyper_cleanup_container(c, pod);
+		return -1;
+	}
+
 	list_add_tail(&c->list, &pod->containers);
 	ret = hyper_setup_container(c, pod);
 	if (ret >= 0)
@@ -627,10 +621,9 @@ static int hyper_new_container(char *json, int length)
 	return ret;
 }
 
-static int hyper_kill_container(char *json, int length)
+static int hyper_kill_container(struct hyper_pod *pod, char *json, int length)
 {
 	struct hyper_container *c;
-	struct hyper_pod *pod = &global_pod;
 	int ret = -1;
 
 	JSON_Value *value = hyper_json_parse(json, length);
@@ -652,10 +645,9 @@ static int hyper_kill_container(char *json, int length)
 	return ret;
 }
 
-static int hyper_remove_container(char *json, int length)
+static int hyper_remove_container(struct hyper_pod *pod, char *json, int length)
 {
 	struct hyper_container *c;
-	struct hyper_pod *pod = &global_pod;
 	int ret = -1;
 
 	JSON_Value *value = hyper_json_parse(json, length);
@@ -719,7 +711,7 @@ static int hyper_open_container_file(void *data)
 	exit(ret);
 }
 
-static int hyper_cmd_rw_file(char *json, int length, uint32_t *rdatalen, uint8_t **rdata, int rw)
+static int hyper_cmd_rw_file(struct hyper_pod *pod, char *json, int length, uint32_t *rdatalen, uint8_t **rdata, int rw)
 {
 	struct file_command cmd = {
 		.id = NULL,
@@ -730,7 +722,6 @@ static int hyper_cmd_rw_file(char *json, int length, uint32_t *rdatalen, uint8_t
 		.rw = rw,
 	};
 	struct hyper_container *c;
-	struct hyper_pod *pod = &global_pod;
 	char *data = NULL;
 	void *stack = NULL;
 	int stacksize = getpagesize() * 4;
@@ -1105,7 +1096,7 @@ static int hyper_ctlmsg_handle(struct hyper_event *he, uint32_t len)
 		hyper_set_be32(data, APIVERSION);
 		break;
 	case STARTPOD:
-		ret = hyper_start_pod((char *)buf->data + 8, len - 8);
+		ret = hyper_start_pod(pod, (char *)buf->data + 8, len - 8);
 		hyper_print_uptime();
 		break;
 	case DESTROYPOD:
@@ -1114,13 +1105,13 @@ static int hyper_ctlmsg_handle(struct hyper_event *he, uint32_t len)
 		hyper_destroy_pod(pod, 0);
 		return 0;
 	case EXECCMD:
-		ret = hyper_exec_cmd((char *)buf->data + 8, len - 8);
+		ret = hyper_exec_cmd(pod, (char *)buf->data + 8, len - 8);
 		break;
 	case WRITEFILE:
-		ret = hyper_cmd_rw_file((char *)buf->data + 8, len - 8, NULL, NULL, WRITEFILE);
+		ret = hyper_cmd_rw_file(pod, (char *)buf->data + 8, len - 8, NULL, NULL, WRITEFILE);
 		break;
 	case READFILE:
-		ret = hyper_cmd_rw_file((char *)buf->data + 8, len - 8, &datalen, &data, READFILE);
+		ret = hyper_cmd_rw_file(pod, (char *)buf->data + 8, len - 8, &datalen, &data, READFILE);
 		break;
 	case PING:
 		break;
@@ -1131,13 +1122,13 @@ static int hyper_ctlmsg_handle(struct hyper_event *he, uint32_t len)
 		ret = hyper_set_win_size(pod, (char *)buf->data + 8, len - 8);
 		break;
 	case NEWCONTAINER:
-		ret = hyper_new_container((char *)buf->data + 8, len - 8);
+		ret = hyper_new_container(pod, (char *)buf->data + 8, len - 8);
 		break;
 	case KILLCONTAINER:
-		ret = hyper_kill_container((char *)buf->data + 8, len - 8);
+		ret = hyper_kill_container(pod, (char *)buf->data + 8, len - 8);
 		break;
 	case REMOVECONTAINER:
-		ret = hyper_remove_container((char *)buf->data + 8, len - 8);
+		ret = hyper_remove_container(pod, (char *)buf->data + 8, len - 8);
 		break;
 	case ONLINECPUMEM:
 		hyper_cmd_online_cpu_mem();