diff --git a/python/ray/projects/scripts.py b/python/ray/projects/scripts.py
index ffc381bdc..6a47a434a 100644
--- a/python/ray/projects/scripts.py
+++ b/python/ray/projects/scripts.py
@@ -6,11 +6,18 @@ import logging
 import os
 import sys
 from shutil import copyfile
-
+import time
 import click
 import jsonschema
 
 import ray
+from ray.autoscaler.commands import (
+    attach_cluster,
+    exec_cluster,
+    create_or_update_cluster,
+    rsync,
+    teardown_cluster,
+)
 
 logging.basicConfig(format=ray.ray_constants.LOGGER_FORMAT)
 logger = logging.getLogger(__file__)
@@ -51,11 +58,11 @@ def project_cli():
 def validate(verbose):
     try:
         project = ray.projects.load_project(os.getcwd())
-        print("🍰 Project files validated!", file=sys.stderr)
+        print("Project files validated!", file=sys.stderr)
         if verbose:
             print(project)
     except (jsonschema.exceptions.ValidationError, ValueError) as e:
-        print("💔 Validation failed for the following reason", file=sys.stderr)
+        print("Validation failed for the following reason", file=sys.stderr)
         raise click.ClickException(e)
 
 
@@ -107,6 +114,142 @@ def create(project_name, cluster_yaml, requirements):
 
 
 @click.group(
-    "session", help="[Experimental] Commands working with ray session")
+    "session",
+    help="[Experimental] Commands working with sessions, which are "
+    "running instances of a project.")
 def session_cli():
     pass
+
+
+def load_project_or_throw():
+    # Validate the project file
+    try:
+        return ray.projects.load_project(os.getcwd())
+    except (jsonschema.exceptions.ValidationError, ValueError):
+        raise click.ClickException(
+            "Project file validation failed. Please run "
+            "`ray project validate` to inspect the error.")
+
+
+@session_cli.command(help="Attach to an existing cluster")
+def attach():
+    project_definition = load_project_or_throw()
+    attach_cluster(
+        project_definition["cluster"],
+        start=False,
+        use_tmux=False,
+        override_cluster_name=None,
+        new=False,
+    )
+
+
+@session_cli.command(help="Stop a session based on current project config")
+def stop():
+    project_definition = load_project_or_throw()
+    teardown_cluster(
+        project_definition["cluster"],
+        yes=True,
+        workers_only=False,
+        override_cluster_name=None)
+
+
+@session_cli.command(help="Start a session based on current project config")
+def start():
+    project_definition = load_project_or_throw()
+
+    # Check for features we don't support right now
+    project_environment = project_definition["environment"]
+    need_docker = ("dockerfile" in project_environment
+                   or "dockerimage" in project_environment)
+    if need_docker:
+        raise click.ClickException(
+            "Docker support in session is currently not implemented. "
+            "Please file an feature request at"
+            "https://github.com/ray-project/ray/issues")
+
+    cluster_yaml = project_definition["cluster"]
+    working_directory = project_definition["name"]
+
+    logger.info("[1/4] Creating cluster")
+    create_or_update_cluster(
+        config_file=cluster_yaml,
+        override_min_workers=None,
+        override_max_workers=None,
+        no_restart=False,
+        restart_only=False,
+        yes=True,
+        override_cluster_name=None,
+    )
+
+    logger.info("[2/4] Syncing the repo")
+    if "repo" in project_definition:
+        # HACK: Skip git clone if exists so the this command can be idempotent
+        # More advanced repo update behavior can be found at
+        # https://github.com/jupyterhub/nbgitpuller/blob/master/nbgitpuller/pull.py
+        session_exec_cluster(
+            cluster_yaml,
+            "git clone {repo} {directory} || true".format(
+                repo=project_definition["repo"],
+                directory=project_definition["name"]),
+        )
+    else:
+        session_exec_cluster(
+            cluster_yaml,
+            "mkdir {directory} || true".format(
+                directory=project_definition["name"]))
+
+    logger.info("[3/4] Setting up environment")
+    _setup_environment(
+        cluster_yaml, project_definition["environment"], cwd=working_directory)
+
+    logger.info("[4/4] Running commands")
+    _run_commands(
+        cluster_yaml, project_definition["commands"], cwd=working_directory)
+
+
+def session_exec_cluster(cluster_yaml, cmd, cwd=None):
+    if cwd is not None:
+        cmd = "cd {cwd}; {cmd}".format(cwd=cwd, cmd=cmd)
+    exec_cluster(
+        config_file=cluster_yaml,
+        cmd=cmd,
+        docker=False,
+        screen=False,
+        tmux=False,
+        stop=False,
+        start=False,
+        override_cluster_name=None,
+        port_forward=None,
+    )
+
+
+def _setup_environment(cluster_yaml, project_environment, cwd):
+
+    if "requirements" in project_environment:
+        requirements_txt = project_environment["requirements"]
+
+        # Create a temporary requirements_txt in the head node.
+        remote_requirements_txt = (
+            "/tmp/" + "ray_project_requirements_txt_{}".format(time.time()))
+
+        rsync(
+            cluster_yaml,
+            source=requirements_txt,
+            target=remote_requirements_txt,
+            override_cluster_name=None,
+            down=False,
+        )
+        session_exec_cluster(
+            cluster_yaml,
+            "pip install -r {}".format(remote_requirements_txt),
+            cwd=cwd)
+
+    if "shell" in project_environment:
+        for cmd in project_environment["shell"]:
+            session_exec_cluster(cluster_yaml, cmd, cwd=cwd)
+
+
+def _run_commands(cluster_yaml, commands, cwd):
+    for cmd in commands:
+        logger.debug("Running {}".format(cmd["name"]))
+        session_exec_cluster(cluster_yaml, cmd["command"], cwd=cwd)
diff --git a/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/cluster.yaml b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/cluster.yaml
new file mode 100644
index 000000000..80c3cd546
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/cluster.yaml
@@ -0,0 +1,18 @@
+# This file is generated by `ray project create`.
+
+# A unique identifier for the head node and workers of this cluster.
+cluster_name: git-repo-pass
+
+# The maximum number of workers nodes to launch in addition to the head
+# node. This takes precedence over min_workers. min_workers defaults to 0.
+max_workers: 1
+
+# Cloud-provider specific configuration.
+provider:
+    type: aws
+    region: us-west-2
+    availability_zone: us-west-2a
+
+# How Ray will authenticate with newly launched nodes.
+auth:
+    ssh_user: ubuntu
diff --git a/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/project.yaml b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/project.yaml
new file mode 100644
index 000000000..e3dcc8f03
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/project.yaml
@@ -0,0 +1,20 @@
+# This file is generated by `ray project create`.
+
+name: git-repo-pass
+
+# description: A short description of the project.
+repo: https://github.com/ray-project/not-exist
+
+cluster: .rayproject/cluster.yaml
+
+environment:
+  # dockerfile: The dockerfile to be built and ran the commands with.
+  # dockerimage: The docker image to be used to run the project in, e.g. ubuntu:18.04.
+  requirements: .rayproject/requirements.txt
+
+  shell: # Shell commands to be ran for environment setup.
+    - echo "Setting up the environment"
+
+commands:
+  - name: first-command
+    command: echo "Starting ray job"
diff --git a/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/requirements.txt b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/requirements.txt
new file mode 100644
index 000000000..0f026d879
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/git-repo-pass/.rayproject/requirements.txt
@@ -0,0 +1 @@
+ray[debug]
\ No newline at end of file
diff --git a/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/cluster.yaml b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/cluster.yaml
new file mode 100644
index 000000000..a084e8c25
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/cluster.yaml
@@ -0,0 +1,18 @@
+# This file is generated by `ray project create`.
+
+# A unique identifier for the head node and workers of this cluster.
+cluster_name: invalid-config-fail
+
+# The maximum number of workers nodes to launch in addition to the head
+# node. This takes precedence over min_workers. min_workers defaults to 0.
+max_workers: 1
+
+# Cloud-provider specific configuration.
+provider:
+    type: aws
+    region: us-west-2
+    availability_zone: us-west-2a
+
+# How Ray will authenticate with newly launched nodes.
+auth:
+    ssh_user: ubuntu
diff --git a/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/project.yaml b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/project.yaml
new file mode 100644
index 000000000..aaccd5614
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/project.yaml
@@ -0,0 +1,23 @@
+# This file is generated by `ray project create`.
+
+name: invalid-config-fail
+
+# description: A short description of the project.
+# repo: The URL of the repo this project is part of.
+
+cluster: .rayproject/cluster.yaml
+
+environment:
+  # NOTE: The following is invalid because you can't have both dockerfile
+  #       and dockerimage
+  dockerfile: The dockerfile to be built and ran the commands with.
+  dockerimage: The docker image to be used to run the project in, e.g. ubuntu:18.04.
+  
+  requirements: .rayproject/requirements.txt
+
+  shell: # Shell commands to be ran for environment setup.
+    - echo "Setting up the environment"
+
+commands:
+  - name: first-command
+    command: echo "Starting ray job"
diff --git a/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/requirements.txt b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/requirements.txt
new file mode 100644
index 000000000..0f026d879
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/invalid-config-fail/.rayproject/requirements.txt
@@ -0,0 +1 @@
+ray[debug]
\ No newline at end of file
diff --git a/python/ray/tests/project_files/session-tests/project-pass/.rayproject/cluster.yaml b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/cluster.yaml
new file mode 100644
index 000000000..dfe8e9b50
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/cluster.yaml
@@ -0,0 +1,18 @@
+# This file is generated by `ray project create`.
+
+# A unique identifier for the head node and workers of this cluster.
+cluster_name: project-pass
+
+# The maximum number of workers nodes to launch in addition to the head
+# node. This takes precedence over min_workers. min_workers defaults to 0.
+max_workers: 1
+
+# Cloud-provider specific configuration.
+provider:
+    type: aws
+    region: us-west-2
+    availability_zone: us-west-2a
+
+# How Ray will authenticate with newly launched nodes.
+auth:
+    ssh_user: ubuntu
diff --git a/python/ray/tests/project_files/session-tests/project-pass/.rayproject/project.yaml b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/project.yaml
new file mode 100644
index 000000000..853096da8
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/project.yaml
@@ -0,0 +1,20 @@
+# This file is generated by `ray project create`.
+
+name: project-pass
+
+# description: A short description of the project.
+# repo: The URL of the repo this project is part of.
+
+cluster: .rayproject/cluster.yaml
+
+environment:
+  # dockerfile: The dockerfile to be built and ran the commands with.
+  # dockerimage: The docker image to be used to run the project in, e.g. ubuntu:18.04.
+  requirements: .rayproject/requirements.txt
+
+  shell: # Shell commands to be ran for environment setup.
+    - echo "Setting up the environment"
+
+commands:
+  - name: first-command
+    command: echo "Starting ray job"
diff --git a/python/ray/tests/project_files/session-tests/project-pass/.rayproject/requirements.txt b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/requirements.txt
new file mode 100644
index 000000000..0f026d879
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/project-pass/.rayproject/requirements.txt
@@ -0,0 +1 @@
+ray[debug]
\ No newline at end of file
diff --git a/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/cluster.yaml b/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/cluster.yaml
new file mode 100644
index 000000000..65e7d1aa1
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/cluster.yaml
@@ -0,0 +1,18 @@
+# This file is generated by `ray project create`.
+
+# A unique identifier for the head node and workers of this cluster.
+cluster_name: with-docker-fail
+
+# The maximum number of workers nodes to launch in addition to the head
+# node. This takes precedence over min_workers. min_workers defaults to 0.
+max_workers: 1
+
+# Cloud-provider specific configuration.
+provider:
+    type: aws
+    region: us-west-2
+    availability_zone: us-west-2a
+
+# How Ray will authenticate with newly launched nodes.
+auth:
+    ssh_user: ubuntu
diff --git a/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/project.yaml b/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/project.yaml
new file mode 100644
index 000000000..fee651853
--- /dev/null
+++ b/python/ray/tests/project_files/session-tests/with-docker-fail/.rayproject/project.yaml
@@ -0,0 +1,19 @@
+# This file is generated by `ray project create`.
+
+name: with-docker-fail
+
+# description: A short description of the project.
+# repo: The URL of the repo this project is part of.
+
+cluster: .rayproject/cluster.yaml
+
+environment:
+  # dockerfile: The dockerfile to be built and ran the commands with.
+  dockerimage: ubuntu:18.04
+
+  shell: # Shell commands to be ran for environment setup.
+    - echo "Setting up the environment"
+
+commands:
+  - name: first-command
+    command: echo "Starting ray job"
diff --git a/python/ray/tests/test_projects.py b/python/ray/tests/test_projects.py
index dba09baaf..9ea319a60 100644
--- a/python/ray/tests/test_projects.py
+++ b/python/ray/tests/test_projects.py
@@ -7,9 +7,19 @@ import os
 import pytest
 import subprocess
 import yaml
+from click.testing import CliRunner
+import sys
 
+from contextlib import contextmanager
+
+from ray.projects.scripts import start
 import ray
 
+if sys.version_info >= (3, 3):
+    from unittest.mock import patch, DEFAULT
+else:
+    from mock import patch, DEFAULT
+
 TEST_DIR = os.path.dirname(os.path.abspath(__file__))
 
 
@@ -65,3 +75,141 @@ def test_project_no_validation():
     path = os.path.join(TEST_DIR, "project_files")
     with pytest.raises(subprocess.CalledProcessError):
         subprocess.check_call(["ray", "project", "validate"], cwd=path)
+
+
+@contextmanager
+def _chdir_and_back(d):
+    old_dir = os.getcwd()
+    try:
+        os.chdir(d)
+        yield
+    finally:
+        os.chdir(old_dir)
+
+
+def test_session_start_default_project():
+    # Run the CLI commands with patching
+    test_dir = os.path.join(TEST_DIR,
+                            "project_files/session-tests/project-pass")
+    with _chdir_and_back(test_dir):
+        runner = CliRunner()
+        with patch.multiple(
+                "ray.projects.scripts",
+                create_or_update_cluster=DEFAULT,
+                rsync=DEFAULT,
+                exec_cluster=DEFAULT,
+        ) as mock_calls:
+            result = runner.invoke(start, [])
+            assert result.exit_code == 0
+
+    # Check we are calling autoscaler correctly
+    loaded_project = ray.projects.load_project(test_dir)
+
+    # Part 1/3: Cluster Launching Call
+    create_or_update_cluster_call = mock_calls["create_or_update_cluster"]
+    assert create_or_update_cluster_call.call_count == 1
+    _, kwargs = create_or_update_cluster_call.call_args
+    assert kwargs["config_file"] == loaded_project["cluster"]
+
+    # Part 2/3: Rsync Calls
+    rsync_call = mock_calls["rsync"]
+    assert rsync_call.call_count == 1
+    _, kwargs = rsync_call.call_args
+    assert kwargs["source"] == loaded_project["environment"]["requirements"]
+
+    # Part 3/3: Exec Calls
+    exec_cluster_call = mock_calls["exec_cluster"]
+    commands_executed = []
+    for _, kwargs in exec_cluster_call.call_args_list:
+        commands_executed.append(kwargs["cmd"].replace(
+            "cd {}; ".format(loaded_project["name"]), ""))
+
+    expected_commands = loaded_project["environment"]["shell"]
+    expected_commands += [
+        command["command"] for command in loaded_project["commands"]
+    ]
+
+    if "requirements" in loaded_project["environment"]:
+        assert any("pip install -r" for cmd in commands_executed)
+        # pop the `pip install` off commands executed
+        commands_executed = [
+            cmd for cmd in commands_executed if "pip install -r" not in cmd
+        ]
+
+    # if we don't have a repo, we will be creating a directory
+    if "repo" not in loaded_project:
+        mkdir_command = "mkdir {project_name}".format(
+            project_name=loaded_project["name"])
+        assert any(mkdir_command in cmd for cmd in commands_executed)
+        # pop the `pip install` off commands executed
+        commands_executed = [
+            cmd for cmd in commands_executed if mkdir_command not in cmd
+        ]
+
+    assert expected_commands == commands_executed
+
+
+def test_session_start_docker_fail():
+    # Run the CLI commands with patching
+    test_dir = os.path.join(TEST_DIR,
+                            "project_files/session-tests/with-docker-fail")
+    with _chdir_and_back(test_dir):
+        runner = CliRunner()
+        with patch.multiple(
+                "ray.projects.scripts",
+                create_or_update_cluster=DEFAULT,
+                rsync=DEFAULT,
+                exec_cluster=DEFAULT,
+        ) as _:
+            result = runner.invoke(start, [])
+            assert result.exit_code == 1
+            assert ("Docker support in session is currently "
+                    "not implemented") in result.output
+
+
+def test_session_git_repo_cloned():
+    # Run the CLI commands with patching
+    test_dir = os.path.join(TEST_DIR,
+                            "project_files/session-tests/git-repo-pass")
+    with _chdir_and_back(test_dir):
+        runner = CliRunner()
+        with patch.multiple(
+                "ray.projects.scripts",
+                create_or_update_cluster=DEFAULT,
+                rsync=DEFAULT,
+                exec_cluster=DEFAULT,
+        ) as mock_calls:
+            result = runner.invoke(start, [])
+            assert result.exit_code == 0
+
+    loaded_project = ray.projects.load_project(test_dir)
+
+    exec_cluster_call = mock_calls["exec_cluster"]
+    commands_executed = []
+    for _, kwargs in exec_cluster_call.call_args_list:
+        command_executed = kwargs["cmd"]
+        # Filter out the cd call that was appended to each command
+        cd_project_dir_call = "cd {}; ".format(loaded_project["name"])
+        command_executed = command_executed.replace(cd_project_dir_call, "")
+        commands_executed.append(command_executed)
+
+    assert any("git clone" in cmd for cmd in commands_executed)
+
+
+def test_session_invalid_config_errored():
+    # Run the CLI commands with patching
+    test_dir = os.path.join(TEST_DIR,
+                            "project_files/session-tests/invalid-config-fail")
+    with _chdir_and_back(test_dir):
+        runner = CliRunner()
+        with patch.multiple(
+                "ray.projects.scripts",
+                create_or_update_cluster=DEFAULT,
+                rsync=DEFAULT,
+                exec_cluster=DEFAULT,
+        ) as _:
+            result = runner.invoke(start, [])
+            assert result.exit_code == 1
+            assert "validation failed" in result.output
+            # check that we are displaying actional error message
+            assert "ray project validate" in result.output