Forward SSH port

[ckunki]

ITDE currently uses docker_exec to access the Docker Container, e.g. to analyze the content of some logfiles. With version 8 and higher the format of the Docker Containers might change so that docker_exec is no longer possible. Instead ITDE will then need to use SSH access.

The current ticket requests to to forward the SSH port outside the Docker Container in order to enable accessing the operating system hosting the database via SSH from outside the Docker Container.

Acceptance Criteria

1. ITDE offers a cli option --ssh-port-forward to specify the port mapping
2. user guide describes new cli option
3. ITDE implementation handles the command line option in API, test environment, and luigi task
4. If the container does not exist already and user did not specify a port then ITDE selects a random port from the list of free ports available on the host system outside the docker
5. If the container exists already then ITDE
   • reuses the existing container
   • inquires the forwarded port from the container
   • ignores the command line option

[ckunki]

Affected are

1. cli/options/test_environment_options.py defines new cli option
2. lib/test_environment/parameter/docker_db_test_environment_parameter.py defines new task parameter
3. lib/test_environment/spawn_test_database.py forwards the SSH port accordingly
4. cli/commands/spawn_test_environment.py
5. lib/api/spawn_test_environment_with_test_container.py
6. lib/api/spawn_test_environment.py
7. testing/exaslct_test_environment.py

Proposed changes for (3):

SSH_PORT = "22"
if self.ssh_port_forward is not None:
    ports[f"{SSH_PORT}/tcp"] = ('0.0.0.0', int(self.ssh_port_forward))

[ckunki]

Discussion with @tkilias:

• forwarded port should be random
• implementation should select a free port automatically
• If container is already existing then the forwarded port that had been selected previously should be reused

For reuse:

• see How do I find container ports? docker/docker-py#1742
• port_data = client.inspect_container(<container_id>)['NetworkSettings']['Ports']

or

def get_mapped_port(container: Container, port: int) -> int:
    try:
        return int(
            container.attrs
            ["HostConfig"]
            ["PortBindings"]
            [f"{port}/tcp"]
            [0]
            ["HostPort"]
        )
    except (KeyError, IndexError):
        return None

Example from container.attrs:

   "PortBindings": {
     "6583/tcp": [{"HostIp": "0.0.0.0", "HostPort": "36263"}],
     "8888/tcp": [{"HostIp": "0.0.0.0", "HostPort": "50033"}]
   },

[ckunki]

See exasol_integration_test_docker_environment.testing.utils.find_free_ports.

Used in exasol_integration_test_docker_environment/testing/api_test_environment.py:

database_port, bucketfs_port = find_free_ports(2)

Implementation options

• a) always allocate 3 ports in advance, and only use 3rd port for SSH in case SSH access is required
• b) stick with on 2 allocated ports in advance, and allocate a 3rd one dynamically later on if required
• c) analyze cli options to identify if a 3rd port needs to be allocated in advance

I opt for option (c).

[ckunki]

Observations indicate that some logic in Docker seems to overwrite file /root/.ssh/authorized_keys.

Which alternatives exist?

• A1) Modify logic in Docker to not overwrite the file and rather append additional keys if required.
• A2) Change our code to modify the file at a later point in time and append to file rather than overwriting it.
• A3) Authenticate with password instead of keys.
• A4) Use key of existing logic in Docker.

For A1 and A2 feasibility is unknown.
A3 and A4 require to know either password or the secret key in advance.

[tkilias]

Extend docker db EXAConf template with

integration-test-docker-environment/docker_db_config_template/8.17.0/EXAConf

Line 86 in 74396e4

AdditionalGroups = exausers, exaadm, exadbadm, exastoradm, exabfsadm, exasaasadm

add authorized_keys config to root user with like that

authorized_keys = {{ authorized_keys }}

[ckunki]

After changing one of the templates, e.g. docker_db_config_template/7.1.0/EXAConf you might need to copy the templates to folder exasol_integration_test_docker_environment/docker_db_config with the following command:

bash ./githooks/update_packaging.sh

Inside the Docker Container the following commands might be helpful:

• exaconf list-users to check the results from evaluating file /exa/etc/EXAConf
• exaconf modify-user --name root --auth-keys <my-key> to modify auth keys without editing file /exa/etc/EXAConf

[tkilias]

the issue is, in the c4 container, you can't access the exaconf and exaconf changes the config file, but not the applied config, for that exainit needs to run again.

[tkilias]

if you want to change the user in a running container, you probably need to use confd.

[ckunki]

No worries, currently I have some progress and I already could find out that the key in EXAConf is not authorized_keys but AuthorizedKeys. 🙂

[ckunki]

Open questions

ID	File	Question	Proposal
Q1	eitde/lib/test_environment/parameter/external_test_environment_parameter.py	Which default value to use for SSH port for external exasol database?	22
Q2	eitde/cli/options/test_environment_options.py	Should cli option --external-exasol-ssh-port be mandatory or optional?	optional
Q3	eitde/lib/test_environment/spawn_test_environment.py	See question Q2, Should missing SSH port raise an exception here, too?	No
Q4	pytest_itde/__init__.py	Which port should be used for ssh_port_forward?	22
Q6	eitde/lib/api/spawn_test_environment.py	Do we accept a breaking change to API?	?
Q7	eitde/lib/api/spawn_test_environment_with_test_container.py	See Q6	?
Q8	eitde/lib/data/database_info.py	See Q6	?
Q9	doc/user_guide/user_guide.rst eitde/lib/test_environment/abstract_spawn_test_environment.py	user_guide.rst describes file environment_info.sh to contain "export" statement for each variable, while implemention does not generate "export" statements. Which file should be updated?	user_guide.rst

[ckunki]

Dear reviewers: I updated the PR #339 and fixed most review findings.
Only remaining (to my knowledge) is discussion #1219777763.

[ckunki]

Dear reviewers I fixed findings from round No. 2.
Please review again.

[ckunki]

Blocked by #351

[ckunki]

blocking issue #351 has been implemented and released with version 1.7.1 - removing label blocked:yes

[ckunki]

Ready for Review again.