Discard mounts when attaching to an existing container

Signed-off-by: Felix Abecassis <[email protected]>
NVIDIA · Feb 25, 2022 · 54b34b0 · 54b34b0
1 parent 071de4b
commit 54b34b0
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Showing 4 changed files with 32 additions and 8 deletions.
diff --git a/args.c b/args.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
+ * Copyright (c) 2020-2022, NVIDIA CORPORATION. All rights reserved.
  */
 
 #include <stdio.h>
@@ -229,6 +229,16 @@ int add_mount(const char *source, const char *target, const char *flags)
 	return (rv);
 }
 
+void remove_all_mounts(void)
+{
+	for (int i = 0; i < pyxis_args.mounts_len; ++i)
+		free(pyxis_args.mounts[i]);
+	free(pyxis_args.mounts);
+
+	pyxis_args.mounts = NULL;
+	pyxis_args.mounts_len = 0;
+}
+
 static int parse_mount_option(const char *option)
 {
 	int ret;
@@ -460,9 +470,7 @@ bool pyxis_args_enabled(void)
 void pyxis_args_free(void)
 {
 	free(pyxis_args.image);
-	for (int i = 0; i < pyxis_args.mounts_len; ++i)
-		free(pyxis_args.mounts[i]);
-	free(pyxis_args.mounts);
+	remove_all_mounts();
 	free(pyxis_args.workdir);
 	free(pyxis_args.container_name);
 	free(pyxis_args.container_save);

diff --git a/args.h b/args.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
+ * Copyright (c) 2020-2022, NVIDIA CORPORATION. All rights reserved.
  */
 
 #ifndef ARGS_H_
@@ -29,6 +29,8 @@ bool pyxis_args_enabled(void);
 
 int add_mount(const char *source, const char *target, const char *flags);
 
+void remove_all_mounts(void);
+
 void pyxis_args_free(void);
 
 #endif /* ARGS_H_ */
diff --git a/pyxis_slurmstepd.c b/pyxis_slurmstepd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION. All rights reserved.
+ * Copyright (c) 2019-2022, NVIDIA CORPORATION. All rights reserved.
  */
 
 #include <linux/limits.h>
@@ -938,6 +938,11 @@ int slurm_spank_user_init(spank_t sp, int ac, char **av)
 		context.container.temporary = true;
 	}
 
+	if (context.container.reuse_ns && context.args->mounts_len > 0) {
+		slurm_spank_log("pyxis: ignoring --container-mounts when attaching to a running container");
+		remove_all_mounts();
+	}
+
 	if (context.args->container_save != NULL)
 		context.container.save_path = strdup(context.args->container_save);
 

diff --git a/tests/exec.bats b/tests/exec.bats
@@ -27,13 +27,22 @@ function teardown() {
     run_srun --container-name=exec-test --container-remap-root bash -c "mount -t tmpfs none /mymnt && sleep 30s" &
 
     sleep 5s # FIXME...
-    run_srun --container-name=exec-test findmnt /mymnt
+    run_srun --overlap --container-name=exec-test findmnt /mymnt
 }
 
 @test "attach to running container after directory change" {
     run_srun --container-image=ubuntu:20.04 --container-name=exec-test bash -c "cd /var && sleep 30s" &
 
     sleep 5s
-    run_srun --container-name=exec-test pwd
+    run_srun --overlap --container-name=exec-test pwd
     [ "${lines[-1]}" == "/" ]
 }
+
+@test "attach to running container with --container--mounts" {
+    run_srun --container-image=ubuntu:20.04 --container-name=exec-test bash -c "sleep 30s" &
+
+    sleep 5s
+    # Verify that --container-mounts is ignored when attaching to a running container.
+    run_srun --overlap --container-name=exec-test --container-mounts /tmp:/mnt/pyxis_test bash -c '[ ! -d "/mnt/pyxis_test" ]'
+    grep -q -- 'ignoring --container-mounts' <<< "${output}"
+}