# Intermittent "Could not resolve host" for a well-known host

**URL:** <https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773>\
**Category:** macOS\
**Created:** [March 23, 2019, 10:33pm UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773 "2019-03-23T22:33:20Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![native-api](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/native-api/32/430_2.png) [@native-api](https://travis-ci.community/u/native-api)\
**Post date:** [March 23, 2019, 10:33pm UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773/1 "2019-03-23T22:33:20Z")

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[Getting build failures due to subj](https://travis-ci.org/native-api/opencv-python/jobs/510386524#L3862) (the build was restarted since, link obsolete) occasionally, roughly once every 40-50 jobs (by perception).

What puzzles me is that the host that has failed to resolve is `homebrew.bintray.com`, the same that was used in lots of previous downloads in the same job, so it must be in the local DNS cache. Isn’t it installed in MacOS builders or something, or has a duration shorter than the job time limit?

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**Author:** ![native-api](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/native-api/32/430_2.png) [@native-api](https://travis-ci.community/u/native-api)\
**Post date:** [March 24, 2019, 12:24pm UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773/2 "2019-03-24T12:24:30Z")

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I restarted the build I’ve linked to in the previous message, so that link is no longer valid.

Hit this again today: [https://travis-ci.org/skvark/opencv-python/jobs/510371063#L8559](https://travis-ci.org/skvark/opencv-python/jobs/510371063#L8559) (this is a PR build so I can’t restart it and this link should stay valid). This time, `homebrew.bintray.com` and `github.com` failed to resolve. This happened shortly after the 20 minutes mark.

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**Author:** ![native-api](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/native-api/32/430_2.png) [@native-api](https://travis-ci.community/u/native-api)\
**Post date:** [March 24, 2019, 1:11pm UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773/3 "2019-03-24T13:11:42Z")

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Got a failure in Linux, too: [https://travis-ci.org/skvark/opencv-python/jobs/510375131#L4477](https://travis-ci.org/skvark/opencv-python/jobs/510375131#L4477) , for `pypi.org`, with many retries.

When all the ~350 jobs that I scheduled yesterday finish, I’ll be able to give the full stats on how frequent this error is.

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<div class="post-metadata">

**Author:** ![native-api](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/native-api/32/430_2.png) [@native-api](https://travis-ci.community/u/native-api)\
**Post date:** [March 25, 2019, 7:03am UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773/4 "2019-03-25T07:03:44Z")

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| | osx | DNS fails | linux | DNS fails | Σ jobs | Σ fails |
| --- | --- | --- | --- | --- | --- | --- |
| [https://travis-ci.org/skvark/opencv-python/builds/510371038](https://travis-ci.org/skvark/opencv-python/builds/510371038) | 39 | 1 | 47 | | 86 | 1 |
| [https://travis-ci.org/skvark/opencv-python/builds/510373939](https://travis-ci.org/skvark/opencv-python/builds/510373939) | 40 | | 48 | | 88 | 0 |
| [https://travis-ci.org/skvark/opencv-python/builds/510375066](https://travis-ci.org/skvark/opencv-python/builds/510375066) | 20 | | 48 | 1 | 68 | 1 |
| [https://travis-ci.org/skvark/opencv-python/builds/510386616](https://travis-ci.org/skvark/opencv-python/builds/510386616) | 40 | | 48 | | 88 | 0 |
| [https://travis-ci.org/native-api/opencv-python/builds/510386513](https://travis-ci.org/native-api/opencv-python/builds/510386513) (1 job restarted) | 41 | 1 | 48 | | 89 | 1 |
| [https://travis-ci.org/native-api/opencv-python/builds/510854165](https://travis-ci.org/native-api/opencv-python/builds/510854165) (14 jobs restarted) | 34 | 11 | 48 | | 82 | 11 |
| Σ | 214 | 13 | 287 | 1 | 501 | 14 |
| | | | | | avg | 35,79 |

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<div class="post-metadata">

**Author:** ![native-api](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/native-api/32/430_2.png) [@native-api](https://travis-ci.community/u/native-api)\
**Post date:** [March 25, 2019, 4:04pm UTC](https://travis-ci.community/t/intermittent-could-not-resolve-host-for-a-well-known-host/2773/5 "2019-03-25T16:04:36Z")

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Had a surge of DNS errors in the last build, updated the table.
