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KNOX-843 - Client side HA #380

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Merged
moresandeep merged 2 commits into from
Oct 23, 2020
Merged

KNOX-843 - Client side HA #380

moresandeep merged 2 commits into from
Oct 23, 2020

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@moresandeep
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@moresandeep moresandeep commented Oct 5, 2020 •
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What changes were proposed in this pull request?

This PR introduces a way for Knox to load balance backend clients. This is done by introducing 3 parameters in HaProvider

  1. enableStickySession - Enables sticky sessions
  2. stickySessionCookieName - Customize sticky session cookie name, default is KNOX_BACKEND-{serviceName}
  3. noFallback - when this flag is set, Knox will return a 502 (Bad Gateway) if a request comes with a cookie and the corresponding backend is unavailable. This is applicable only when stickySessionCookieName is enabled.
  4. enableLoadBalancing - Enable loadbalancing, roundrobin requests to backend HA urls
     <provider>
            <role>ha</role>
            <name>HaProvider</name>
            <enabled>true</enabled>
            <param>
                <name>WHOAMI</name>
                <value>enabled=true;maxFailoverAttempts=3;failoverSleep=1000;enableStickySession=true;noFallback=true</value>
            </param>
        </provider>

When enabled, knox dispatch will round-robin requests to the URLs listed in the HA configuration unlike previously where knox only chooses other URL after a failover.
The sessions are sticky so same session requests will always end up dispatching to the same backend.

How was this patch tested?

This patch was manually tested using

  1. curl for multiple different sessions
(base) ➜  temp curl -iku admin:admin-password  "https://localhost:8443/gateway/test/whoami/"
HTTP/1.1 200 OK
Date: Mon, 05 Oct 2020 19:20:03 GMT
Set-Cookie: KNOXSESSIONID=node0flaeprbtixj919ozympe23muc2.node0; Path=/gateway/test; Secure; HttpOnly
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Set-Cookie: rememberMe=deleteMe; Path=/gateway/test; Max-Age=0; Expires=Sun, 04-Oct-2020 19:20:04 GMT
Set-Cookie: KNOX_BACKEND-WHOAMI=4336ad0a09ba5de5c19d294a6e1be4bd5b0aa62bc0537b2c1951ad50b1aca033; Path=/gateway/test; Secure; HttpOnly
Content-Length: 10

 SERVER 1
(base) ➜  temp curl -iku admin:admin-password  "https://localhost:8443/gateway/test/whoami/"
HTTP/1.1 200 OK
Date: Mon, 05 Oct 2020 19:20:05 GMT
Set-Cookie: KNOXSESSIONID=node01bynsokjpm43t1ag2zogir8wht3.node0; Path=/gateway/test; Secure; HttpOnly
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Set-Cookie: rememberMe=deleteMe; Path=/gateway/test; Max-Age=0; Expires=Sun, 04-Oct-2020 19:20:05 GMT
Set-Cookie: KNOX_BACKEND-WHOAMI=d2eea4def3bbb002420943cc4d7983627cf7132b6154a400597c379a1254189b; Path=/gateway/test; Secure; HttpOnly
Content-Length: 10

 SERVER 2
  1. curl for sticky sessions
(base) ➜  temp curl -iku admin:admin-password -c cookies.txt -b cookies.txt "https://localhost:8443/gateway/test/whoami/"

HTTP/1.1 200 OK
Date: Mon, 05 Oct 2020 19:22:05 GMT
Set-Cookie: KNOXSESSIONID=node0117mojjq6uevh1p1nl2v5iumgo5.node0; Path=/gateway/test; Secure; HttpOnly
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Set-Cookie: rememberMe=deleteMe; Path=/gateway/test; Max-Age=0; Expires=Sun, 04-Oct-2020 19:22:06 GMT
Set-Cookie: KNOX_BACKEND-WHOAMI=d2eea4def3bbb002420943cc4d7983627cf7132b6154a400597c379a1254189b; Path=/gateway/test; Secure; HttpOnly
Content-Length: 10

 SERVER 2
(base) ➜  temp curl -iku admin:admin-password -c cookies.txt -b cookies.txt "https://localhost:8443/gateway/test/whoami/"

HTTP/1.1 200 OK
Date: Mon, 05 Oct 2020 19:22:06 GMT
Content-Length: 10

 SERVER 2
(base) ➜  temp curl -iku admin:admin-password -c cookies.txt -b cookies.txt "https://localhost:8443/gateway/test/whoami/"

HTTP/1.1 200 OK
Date: Mon, 05 Oct 2020 19:22:07 GMT
Content-Length: 10

 SERVER 2
  1. curl with sticky sessions with fallback off
(base) ➜  temp curl  -iku admin:admin-password -c cookies.txt -b cookies.txt "https://localhost:8443/gateway/test/whoami/"
HTTP/1.1 502 Bad Gateway
Cache-Control: must-revalidate,no-cache,no-store
Content-Type: text/html;charset=iso-8859-1
Content-Length: 507

<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
<title>Error 502 Service connection error, HA failover disabled</title>
</head>
<body><h2>HTTP ERROR 502 Service connection error, HA failover disabled</h2>
<table>
<tr><th>URI:</th><td>/gateway/test/whoami/</td></tr>
<tr><th>STATUS:</th><td>502</td></tr>
<tr><th>MESSAGE:</th><td>Service connection error, HA failover disabled</td></tr>
<tr><th>SERVLET:</th><td>test-knox-gateway-servlet</td></tr>
</table>

</body>
</html>
  1. Browser

@moresandeep
KNOX-843 - Added enableLoadBalancing config, updated variables names …
67836d4 
…to enableStickySession and stickySessionCookieName
@moresandeep moresandeep force-pushed the KNOX-843_ClidentSide_HA branch from b9d21c4 to 67836d4 Compare October 22, 2020 19:16
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moresandeep commented Oct 22, 2020

@lmccay I updated the PR with requested changes go through it and let me know what you think. I had to do some refactoring because I realized that we have a ton of custom HA implementations (e.g. Atlas) which would not get this feature because of how they just extended DefaultHADispatch. I did some refactoring so that custom dispatches should be able to use these flags.

@moresandeep moresandeep merged commit 673bb4b into apache:master Oct 23, 2020
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@lmccay lmccay Awaiting requested review from lmccay

@risdenk risdenk Awaiting requested review from risdenk

@pzampino pzampino Awaiting requested review from pzampino

@smolnar82 smolnar82 Awaiting requested review from smolnar82

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