Neutron metadata agent fails with RequestURITooLong

The problem description:

The number of private networks (internal networks for the instances) is limited by the fact that the curl requests that instances make (i.e. curl -I http://<server IP>/2009-04-04/meta-data/instance-id/) returns the ENTIRE list of networks, and at a certain point this exceed the 8190 URI length limit for apache (which neutron-metadata-agent uses as webserver backend).
Here is the URI that the metadata curl request generates on the OpenStack side in case:

/v2.0/ports.json?network_id=ce1dc3ce-6a23-4067-b97b-2d774b95a38e&network_id=108fef5f-fcaa-4c61-a9eb-0aed4ca27638&network_id=ce1e0a35-bddf-46b2-a6e4-a285310ee27b&network_id=7329c284-69c5-4085-8c4b-a423968f277c&network_id=25d51663-2aca-4cfd-8351-ebb6fe6ac21e&network_id=47968396-8dcf-45d2-b7ca-7b142779606b&network_id=f1d8fcc5-74dd-4e45-897f-acfc349bf214&network_id=ab868487-0b8f-4f2d-9fa7-07cef6a4d08c&network_id=d6c62b22-46b7-4bf6-9973-12c7366ee0aa&network_id=13d809ad-34e9-4c7e-a89e-3b1d0ad46516&network_id=9a45b6af-98c2-41da-9742-0f1be9653a7f&network_id=cd4ebaea-9437-4ed1-834d-6ba1285f458e&network_id=7ad5b66b-c913-429f-9608-0df761d4a1c0&network_id=1cc8e42f-f8d7-47cc-89a9-084193388529&network_id=eaa69786-f63c-4576-9798-f6e6e1781b77&network_id=4f24a32a-5066-4dfd-9564-bb0175ba398a&network_id=f82890ec-4422-499d-b9b2-991c4db133a7&network_id=d18aa4b6-4336-4813-876a-b1e036020691&network_id=e767f01a-3874-4cbd-95c9-821cb597e584&network_id=00fb2bef-fd6d-4bd7-afd2-21b792f2d327&network_id=54234780-1867-4aca-8c84-9da17f57fb64&network_id=d5fc9a5b-b211-40a9-9a10-80132a59abf9&network_id=3eeb9b41-c7ee-4b92-bb0e-fcee30877e6b&network_id=7cf2db1f-0b45-42fc-acf1-e1e5f7d37f9a&network_id=7c0f8b11-e6b6-4d0a-9b75-62a849c310d4&network_id=58af0513-8ab2-4dc8-8303-3f75f0ee1915&network_id=e37fd173-71a9-4c85-b15c-a0b43173bcbe&network_id=a1bcf2d1-1dee-45dc-8554-6776197609b8&network_id=8867cc58-044a-4f43-aea9-0c3616509c14&network_id=f453ba4a-68f1-4e78-9ee9-f6236b1e26cd&network_id=eef09a5e-6c38-4ae9-9375-d4dffce96465&network_id=caeb38af-bd77-48bd-bc7a-54267d15d386&network_id=20209828-2b66-4d6d-a6ed-11bbe97ae2f7&network_id=8ce7b415-eede-4d84-bcc8-5b5342560b05&network_id=8883efbf-5a07-4c95-b140-85e038c2f8fe&network_id=5a5fb19d-8fc3-483c-9d17-fbe011849a46&network_id=dfc92ac5-9d2a-4e98-b08c-d40765e0f8a3&network_id=966a9801-c42a-4b36-a959-d74d7b355d03&network_id=47994b11-9f14-4708-bc1a-7adc98d4c0e1&network_id=fd48c2d2-bb7d-4886-a890-6f23a3ecdca9&network_id=5b19cee1-8c91-4fda-9d0d-6f6ba6632f56&network_id=bc50eada-2419-4bd2-80d2-86ccd9e1266c&network_id=51bfc8c3-c06a-4ed6-a492-cf55d380ac33&network_id=fb58fce6-be4a-4a46-89a3-bf1ff9ace954&network_id=7892b3d2-216a-4ea3-a45b-f1311180c638&network_id=f32e446b-1a56-42cd-8fe3-9ecae6405bef&network_id=53c8eff9-2657-4a7f-b02a-f86b28411eec&network_id=710af1e4-27af-4393-b46d-30c6e6dbb606&network_id=9e94f25b-e49e-4804-a784-f4c325e727ae&network_id=03933632-a885-474b-acd7-a980ef1120e3&network_id=fabac2ac-ffea-4d1c-8f85-7856a846641f&network_id=bfb0570c-84b8-4c2e-ba62-f011d1950591&network_id=8ef1ccf3-c11c-4010-b6ed-f599d97fb565&network_id=ac3b8389-45d9-4a3b-9188-1059912c8565&network_id=65704511-430c-4760-a78a-21c7b0a1dd2c&network_id=19e16f27-d69f-4d4b-8487-6a7b6d468eb9&network_id=0512afdb-4e54-4bb8-abc7-793975734bb1&network_id=1d2bcb94-1a25-4bbb-88c2-d946d3acc3af&network_id=6e53d931-b036-46fc-b849-81263f11aca7&network_id=56225598-96ec-4d48-b702-a38c9bf6bec5&network_id=312c22f3-1291-4885-bdf9-079cfc2f766b&network_id=cc3083f7-f552-44ac-bad7-7a7e9e880fcb&network_id=10d618bc-0745-4294-be19-2a353756e78d&network_id=24716fa2-2680-4ca9-b026-e2b4b2fd5d08&network_id=8850aafc-ace8-4ac8-87aa-6de25cf6557c&network_id=506a1e17-b2e8-4571-acba-af300c4ccf29&network_id=e1233e15-f839-478f-9328-9c6ceb1e0e4b&network_id=a6c778a5-adf0-4f8f-8460-ead0c9636206&network_id=ae50ed79-221b-4817-b456-82ef1e1285bb&network_id=6192fad1-82ee-4a24-8b6f-c1bbfa62a0e8&network_id=b37e679d-4e96-47d2-b52c-44cb25708132&network_id=6f5146db-cfa4-4ab4-840f-06345a036401&network_id=659672a1-c0d5-408a-9929-a5c5759ec0bf&network_id=45de56b1-2691-409b-a6d0-8a8ba3e16ac6&network_id=9625b113-3a47-441c-a3ea-a649e0274c0f&network_id=b29a85eb-05cc-4f10-aace-fd035b9d49bf&network_id=71a110d7-72a1-4a89-9df5-b5df6d441794&network_id=eca28062-3779-4b4f-95f2-d97eb20def56&network_id=ef65f55b-a908-4777-bbc5-99e821be0c33&network_id=604edad9-4201-47f9-8cad-ecdd1c237973&network_id=35d74d36-f379-4902-9560-112845d64cba&network_id=c47b771d-24d9-491f-af81-fc7451b0a9a9&network_id=3643b5ac-7867-4d72-b7a8-95b623c5100b&network_id=15520eff-7cd3-4baf-a9e2-7a159e0a9687&network_id=8c3e6c37-5067-4b06-b647-07d92faa371f&network_id=8dba215d-5b8e-4811-9a72-dfe4a2a299f7&network_id=a8cf7931-ec7f-4a66-bdf0-62dd1f89a776&network_id=e867f27d-8e7d-4c18-8bd4-aa16358e3a84&network_id=fbe785dd-96ce-45b5-a21c-f07a5bfd6a49&network_id=cc8d3030-363f-46d1-b60d-fd493a4bf399&network_id=1b2afb06-6e3d-417d-9b51-5da7694c5668&network_id=b7d250ef-43a6-4486-83a4-5d52d28fd184&network_id=03a2a12b-9e1a-4f1d-9230-29d79bdaec8a&network_id=a14a8cc3-745c-4bbe-97a8-a62196d19309&network_id=4918e2b1-ecab-4460-a004-006cf870599d&network_id=5d5d670d-b2a2-4c0f-a402-6b7b06572267&network_id=1afeabda-6b11-4d07-a38c-b8c8f45fd1f2&network_id=b84e4ee9-48c6-404c-bc3c-9d70d861c1d3&network_id=ade51ab2-beda-42a1-a5a5-50485bfdfb20&network_id=89c0e381-bbdf-4651-99f5-3c021e775b41&network_id=527f6f7d-c579-496e-b9da-b2892dae2a91&network_id=cbd928ac-a364-4ad0-b3d7-45d11bbd0739&network_id=e91cd98e-7857-4cab-9c9e-c15e0d06988e&network_id=cf52f6b6-5beb-4ef6-8338-b3ec342e6cbe&network_id=e061ef26-3efc-4127-87bc-03ae766bb6cb&network_id=560bb600-bb71-4360-93de-9f5a86c509f4&network_id=0820adfb-047f-4f78-affe-0e4e0cb672a2&network_id=465b64f9-0dc9-4512-b20e-1ae3bd00553f&network_id=46ca8b2e-2fae-4e56-92bc-686b9722dd8c&network_id=96839919-c0b7-44a8-8f62-f4456758dd96&network_id=9af448bd-a978-4d9d-83b8-40b57da2f9e4&network_id=778818eb-9a73-4da5-9c6b-ccc304c63d5f&network_id=15f7b3c9-c45b-44dc-bd16-92c8aff91a5e&network_id=2f35ef62-86d5-4985-b86b-ca444b5d4818&network_id=361f0946-c488-4a72-9338-6168f5c8bd26&network_id=3f7b6859-c2e2-4ceb-8250-2106d2673e82&network_id=91f91a5a-0524-4bd7-bcb1-9bfc89712956&network_id=fcf5f676-8c02-46a8-977b-f0c041043287&network_id=2dc791e1-c12c-4d68-a8b8-2b5589e75974&network_id=c6a761c6-cba4-4248-9829-e1e903a3d3b5&network_id=601cee06-afcf-47e2-a3d3-75247aac4022&network_id=932b404c-0f14-433b-8ba6-9a311007e1b9&network_id=0f82a7e5-294d-41d2-833d-cc69c0564e71&network_id=1b2e4d2b-4e71-4131-87af-a71ce7c1ff36&network_id=4089c593-ef6d-4331-b3bf-67b56f371e08&network_id=5d69a9d4-6517-4b62-ab6e-f39e9eb119a0&network_id=878ee765-bc99-41c7-a5fe-e31bfe0b5339&network_id=b9a15848-0759-4ca7-ad2a-8ab5aeab2898&network_id=e5211cb8-61cc-4f6b-bbae-7f249cf753bd&network_id=435d5e91-75ed-479c-bd9d-0674945fb8be&network_id=6ae531c9-d1a7-495f-9bed-c221ae0e5c8b&network_id=d116c6e1-2573-47b6-81bf-0540b8bc7eb0&network_id=90aa5157-d1be-41ae-9270-a01693b01653&network_id=39994e95-fe11-4878-8811-87e9afd85548&network_id=76b563ae-4f1e-4a2e-8f96-ac80a59b169d&network_id=11d78a66-ca5c-40ad-abca-9c6c0dfd75da&network_id=cbf71b5f-d894-46a2-9567-f4341df5c8e3&network_id=f5f015d6-44e1-454e-89b6-3f04c9c63b06&network_id=f6f2fdc3-2692-4cfe-a356-7743fe785a7a&network_id=3165e8c0-3e7d-428b-845a-e9481c7ae7b0&network_id=ae04bc3f-75a5-4ae8-a3ae-a6042f4a3ca4&network_id=b5f492a4-b6d1-4e20-8649-e4547febdf22&network_id=7d52efaa-76ae-41a1-bb28-4b1c92a8802f&network_id=3d381bf9-f8a3-4b70-8780-0e0b45ded03a&network_id=60548a6f-ed01-4c3a-b9e7-00d6e67b1d35&network_id=b35437a5-0400-40ac-94ec-7661e53f1a62&network_id=f3c7bd67-a3f0-458d-97aa-fd6e339eac7c&network_id=50e1342e-f936-4073-9ba5-c669593df0b7&network_id=b2222aba-f416-4684-8ff7-2e96a8ec0bf8&network_id=a05d8b59-5d07-4cb4-a31e-9016a516b485&network_id=9165faa6-ee87-4b5f-9b9c-f4610bc19df7&network_id=a0856fc7-0328-4bf7-9da7-0503a024b9c6&network_id=7b6025b6-1196-4b6a-8a05-9b53ed92ebba&network_id=cddc61d2-ae24-484c-9508-2d628a8019ee&network_id=5978f660-8353-4be6-859b-3637b3a87090&network_id=8b98dfd8-4685-4093-9944-32f3e1e81245&network_id=532bb319-e78f-4e88-98b3-37bc7d0c5476&network_id=1b84bffa-0625-4fe1-b563-204bd922056c&network_id=764824d9-9e55-4032-a433-8cbd306c7507&network_id=ca472d10-a27d-4d07-a704-0c77096925a2&network_id=abb59c35-3a6d-4062-bc56-618b3e6826da&network_id=540f26ff-3fb9-4498-9874-90dca92f0fa4&network_id=6ccb6ac4-be6f-461a-9cb9-ce37c02bd9c8&network_id=eb65a45a-22e9-46b8-bb61-9fc05622886d&network_id=7a87f7e6-1dc6-4bd1-b737-8baa458bc3d2&network_id=e7fcb223-941d-499e-a390-97a120d4fb54&network_id=d927261b-8405-40c4-91b7-26d3b175720c&network_id=dce6ebb4-b1e2-498a-bf01-53d92ea62685&network_id=9cea528a-4dcc-48b4-b062-5ed50b0eed53&network_id=eedda88a-4eb7-4640-8efa-9318cda15957&network_id=3482ad24-1e4d-427b-a90f-ee9b1def596c&network_id=0f502647-a700-4e23-b3e4-f10537ca3804&network_id=296aadee-7961-4a8d-b870-9578b0b2d2e5&network_id=a154e040-5c0b-42ac-9c06-096fa4d2d1b9&network_id=0b1ffdf8-1f4e-4d15-b6be-3065be9cda0a&network_id=98ed63be-b697-4824-b83d-238c558910aa&fixed_ips=ip_address%3D10.0.45.2

As you can see, it’s super long, 8497 characters, this breaks Apache.

Similar case - URI too long; but for security groups https://bugs.launchpad.net/python-neutronclient/+bug/1271462

For this bug fix was applied: https://review.openstack.org/#/c/95990/

Basically - (from code) ‘# 1 char of extra URI len will cause a split in 2 requests’ (https://review.openstack.org/#/c/95990/3/neutronclient/tests/unit/test_cli20_securitygroup.py)

I believe there are more clients, which do not support request splitting by length.

Upstream bug: https://bugs.launchpad.net/neutron/+bug/1348097