PowerDNS backend for RGW » History » Version 1
Jessica Mack, 06/22/2015 03:23 AM
| 1 | 1 | Jessica Mack | h1. PowerDNS backend for RGW |
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| 3 | h3. Summary |
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| 5 | When using multiple RGW regions it's hard to direct traffic to the correct region. If a region receives a request which is for a different region it will answer with a 301 HTTP redirect, but this adds extra TCP and HTTP traffic which increases latency. |
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| 6 | Wrong configuration on the users end could also lead to additional HTTP traffic on a region since it's only responding with 301s instead of serving objects. |
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| 8 | h3. Owners |
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| 10 | * Wido den Hollander (Owner) |
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| 11 | * Name (Affiliation) |
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| 12 | * Name |
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| 14 | h3. Interested Parties |
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| 15 | |||
| 16 | * Name (Affiliation) |
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| 17 | * Name (Affiliation) |
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| 18 | * Name |
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| 20 | h3. Current Status |
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| 22 | Only an idea, but could be turned into code rather quickly. |
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| 23 | Will start with a PoC which won't perform rather well, after that a better version can be written. |
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| 24 | Update: POC written and available as Gist on Github: https://gist.github.com/wido/7664859 |
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| 26 | h3. Detailed Description |
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| 28 | A backend for PowerDNS could solve this where the DNS server answers with a different CNAME depending in the bucket in the hostname. |
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| 29 | The backend has to be aware of the regions and buckets to be able to direct traffic. |
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| 30 | For example, a setup has two regions with each their own endpoint: |
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| 31 | _*US*: o.myobjectstore.us_ |
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| 32 | _*EU*: o.myobjectstore.eu_ |
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| 33 | _*Global*: o.myobjectstore.com _ |
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| 34 | Bucket _'foo'_ is in the region US and bucket _'bar'_ in the EU. |
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| 35 | The DNS server will respond like this: |
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| 36 | foo.o.myobjectstore.com CNAME foo.o.myobjectstore.us |
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| 37 | bar.o.myobjectstore.com CNAME bar.o.myobjectstore.eu |
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| 38 | This can be achieved the the "Remote Backend" support from PowerDNS: http://doc.powerdns.com/html/remotebackend.html |
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| 40 | To improve performance of the backend for PowerDNS the "Agent" will query the REST Admin API of the RGW. |
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| 41 | If that doesn't satisfy the user he/she can put something like Varnish in between to cache HTTP calls and speed up the performance even more. |
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| 43 | h3. Work items |
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| 45 | h4. Coding tasks |
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| 47 | # Write HTTP backend for PowerDNS (Using the RGW REST Admin API) |
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| 48 | # Write a VCL for Varnish |
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| 49 | # Implement cache invalidation on bucket removal |
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| 51 | h4. Build / release tasks |
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| 53 | # Create new DEB and RPM package |
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| 54 | # Task 2 |
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| 55 | # Task 3 |
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| 57 | h4. Documentation tasks |
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| 59 | # Document on how to set up the remote backend and configure it |
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| 60 | # Task 2 |
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| 61 | # Task 3 |
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| 63 | h4. Deprecation tasks |
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| 65 | # Task 1 |
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| 66 | # Task 2 |
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| 67 | # Task 3 |