From 1f860e5ac7ebb5b809c72d8703a0b7cb3e84ccd0 Mon Sep 17 00:00:00 2001 From: Chad Smith Date: Thu, 5 Mar 2020 17:38:28 -0700 Subject: ec2: Do not fallback to IMDSv1 on EC2 (#216) The EC2 Data Source needs to handle 3 states of the Instance Metadata Service configured for a given instance: 1. HttpTokens : optional & HttpEndpoint : enabled Either IMDSv2 or IMDSv1 can be used. 2. HttpTokens : required & HttpEndpoint : enabled Calls to IMDS without a valid token (IMDSv1 or IMDSv2 with expired token) will return a 401 error. 3. HttpEndpoint : disabled The IMDS http endpoint will return a 403 error. Previous work to support IMDSv2 in cloud-init handled case 1 and case 2. This commit handles case 3 by bypassing the retry block when IMDS returns HTTP status code >= 400 on official AWS cloud platform. It shaves 2 minutes when rebooting an instance that has its IMDS http token endpoint disabled but creates some inconsistencies. An instance that doesn't set "manual_cache_clean" to "True" will have its /var/lib/cloud/instance symlink removed altogether after it has failed to find a datasource. --- tests/unittests/test_datasource/test_ec2.py | 48 +++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) (limited to 'tests') diff --git a/tests/unittests/test_datasource/test_ec2.py b/tests/unittests/test_datasource/test_ec2.py index 2a96122f..78e82c7e 100644 --- a/tests/unittests/test_datasource/test_ec2.py +++ b/tests/unittests/test_datasource/test_ec2.py @@ -3,6 +3,7 @@ import copy import httpretty import json +import requests from unittest import mock from cloudinit import helpers @@ -200,6 +201,7 @@ def register_mock_metaserver(base_url, data): class TestEc2(test_helpers.HttprettyTestCase): with_logs = True + maxDiff = None valid_platform_data = { 'uuid': 'ec212f79-87d1-2f1d-588f-d86dc0fd5412', @@ -429,6 +431,52 @@ class TestEc2(test_helpers.HttprettyTestCase): self.assertTrue(ds.get_data()) self.assertFalse(ds.is_classic_instance()) + def test_aws_inaccessible_imds_service_fails_with_retries(self): + """Inaccessibility of http://169.254.169.254 are retried.""" + ds = self._setup_ds( + platform_data=self.valid_platform_data, + sys_cfg={'datasource': {'Ec2': {'strict_id': False}}}, + md=None) + + conn_error = requests.exceptions.ConnectionError( + '[Errno 113] no route to host') + + mock_success = mock.MagicMock(contents=b'fakesuccess') + mock_success.ok.return_value = True + + with mock.patch('cloudinit.url_helper.readurl') as m_readurl: + m_readurl.side_effect = (conn_error, conn_error, mock_success) + with mock.patch('cloudinit.url_helper.time.sleep'): + self.assertTrue(ds.wait_for_metadata_service()) + + # Just one /latest/api/token request + self.assertEqual(3, len(m_readurl.call_args_list)) + for readurl_call in m_readurl.call_args_list: + self.assertIn('latest/api/token', readurl_call[0][0]) + + def test_aws_token_403_fails_without_retries(self): + """Verify that 403s fetching AWS tokens are not retried.""" + ds = self._setup_ds( + platform_data=self.valid_platform_data, + sys_cfg={'datasource': {'Ec2': {'strict_id': False}}}, + md=None) + token_url = self.data_url('latest', data_item='api/token') + httpretty.register_uri(httpretty.PUT, token_url, body={}, status=403) + self.assertFalse(ds.get_data()) + # Just one /latest/api/token request + logs = self.logs.getvalue() + failed_put_log = '"PUT /latest/api/token HTTP/1.1" 403 0' + expected_logs = [ + 'WARNING: Ec2 IMDS endpoint returned a 403 error. HTTP endpoint is' + ' disabled. Aborting.', + "WARNING: IMDS's HTTP endpoint is probably disabled", + failed_put_log + ] + for log in expected_logs: + self.assertIn(log, logs) + self.assertEqual( + 1, len([l for l in logs.splitlines() if failed_put_log in l])) + def test_aws_token_redacted(self): """Verify that aws tokens are redacted when logged.""" ds = self._setup_ds( -- cgit v1.2.3