diff --git a/octane/util/__init__.py b/octane/util/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/octane/util/docker.py b/octane/util/docker.py
new file mode 100644
index 00000000..a45ae592
--- /dev/null
+++ b/octane/util/docker.py
@@ -0,0 +1,58 @@
+import contextlib
+import os.path
+import subprocess
+import tarfile
+
+
+def in_container(container, args, **popen_kwargs):
+    """Create Popen object to run command defined by list args in container"""
+    return subprocess.Popen(["dockerctl", "shell", container] + args,
+                            **popen_kwargs)
+
+
+def compare_files(container, local_filename, docker_filename):
+    """Check if file local_filename equals file docker_filename in container"""
+    with open(local_filename, 'rb') as f:
+        local_contents = f.read()
+    proc = in_container(container, ["cat", docker_filename],
+                        stdout=subprocess.PIPE)
+    docker_contents, _ = proc.communicate()
+    assert proc.returncode == 0
+    # TODO: compare by chunks
+    return docker_contents == local_contents
+
+
+def find_files(source_dir):
+    """Recursively find all files in source_dir
+    
+    Returns tuple of full path and path relative to source_dir for each
+    file."""
+    for cur_dir, subdirs, files in os.walk(source_dir):
+        assert cur_dir.startswith(source_dir)
+        new_dir = cur_dir[len(source_dir) + 1:]
+        for f in files:
+            yield os.path.join(cur_dir, f), os.path.join(new_dir, f)
+
+
+def put_files_to_docker(container, prefix, source_dir):
+    """Put all files in source_dir to prefix dir in container"""
+    source_dir = os.path.abspath(source_dir)
+    # TODO: watch after stdout/stderr here
+    proc = in_container(
+        container,
+        ["tar", "-xv", "--overwrite", "-f", "-", "-C", prefix],
+        stdin=subprocess.PIPE,
+    )
+    tar = tarfile.TarFile(fileobj=proc.stdin, mode='w')
+    with contextlib.closing(tar):
+        for local_filename, docker_filename in find_files(source_dir):
+            tar.add(local_filename, docker_filename)
+    proc.wait()
+    assert proc.returncode == 0  # Don't inline with proc.wait()!
+    for local_filename, docker_filename in find_files(source_dir):
+    for cur_dir, subdirs, files in os.walk(source_dir):
+        if not compare_files(container, local_filename, docker_filename):
+            raise Exception(
+                "Contents of {0} differ from contents of {1} in container {2}"
+                .format(local_filename, docker_filename, container)
+            )