After installing and configuring HCL Component Pack 6.5, I navigated to https://<cnx-ihs-host>/social/home and saw parts of OrientMe with some errors:
The browser console shows multiple http 500 errors, for example https://cnx-ihs-host/community_suggestions/api/recommend/communities?count=30
{"errorMessage":"Bad XML response from Search Application: Error: Unexpected close tag\nLine: 11\nColumn: 7\nChar: >","error":"Error: Error: Unexpected close tag\nLine: 11\nColumn: 7\nChar: >\n at getCommunitiesFromAtom (/home/ibm/app/lib/server/suggestedCommunitiesService.js:98:11)\n at Request.request [as _callback] (/home/ibm/app/lib/server/suggestedCommunitiesService.js:163:19)\n at Request.self.callback (/home/ibm/app/node_modules/request/request.js:185:22)\n at emitTwo (events.js:126:13)\n at Request.emit (events.js:214:7)\n at Request.<anonymous> (/home/ibm/app/node_modules/request/request.js:1161:10)\n at emitOne (events.js:116:13)\n at Request.emit (events.js:211:7)\n at IncomingMessage.<anonymous> (/home/ibm/app/node_modules/request/request.js:1083:12)\n at Object.onceWrapper (events.js:313:30)\n at emitNone (events.js:111:20)\n at IncomingMessage.emit (events.js:208:7)\n at endReadableNT (_stream_readable.js:1064:12)\n at _combinedTickCallback (internal/process/next_tick.js:139:11)\n at process._tickCallback (internal/process/next_tick.js:181:9)"}
So I increment the IHS log to debug and found the following entry:
[debug] mod_proxy_http.c(63): proxy: HTTP: canonicalising URL //cnx-ihs-host/community_suggestions/api/recommend/communities
...
[debug] vhost.c(791): [client 1.2.3.4:44004] [strict] Invalid host name 'cnx65.ihs-host, cnx65.ihs-host', problem near: , cnx6
[debug] vhost.c(886): [client 172.19.34.4:44004] Client sent malformed Host header: cnx65-test-daniel.k8s02.company.internal, cnx65.ihs-host
For me this seems that the hostname was set multiple times like this:
Host: cnx65.ihs-host, cnx65.ihs-host
Why does this happend and how could it be fixed?
Analysis on k8s component pack
I searched for the source, which seems the community-suggestions deployment. For easier troubleshooting (just have to watch 1 pod instead of 3), the deployment was downgraded from 3 to 1 replicas:
kubectl scale deploy community-suggestions --replicas=1
Now there is just a single pod. To get more detailled output, I found the env variable LOG_LEVEL which was stick to info. So I used kubectl edit deploy community-suggestions to set it to debug. This gave me much more infos:
{"pid":23,"hostname":"community-suggestions-bdc8c6577-cxz5x","name":"community-suggestions/lib/server/suggestedCommunitiesService.js","level":30,"time":1583489495149,"msg":"Fetching Community Details using Blue API: https://cnx-ihs-host/search/atom/mysearch?returnType=json&constraint={'type':'field','id':'id','values':[\"ac16d726-118c-4876-a1fd-7f0574aa4cf3\",\"COMMUNITIES\"],'exactMatch':true}&scope=communities:entry","v":1}
2020-03-06T10:11:35.149Z - debug: [orient-web-client] ENTRY: RequestAuthUtils.sanitizeHeaders undefined
2020-03-06T10:11:35.149Z - debug: [orient-web-client] EXIT: RequestAuthUtils.sanitizeHeaders undefined
{"pid":23,"hostname":"community-suggestions-bdc8c6577-cxz5x","name":"community-suggestions/lib/server/suggestedCommunitiesService.js","level":20,"time":1583489495180,"msg":">> getCommunitiesFromAtom <!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n<html><head>\n<title>400 Bad Request</title>\n</head><body>\n<h1>Bad Request</h1>\n<p>Your browser sent a request that this server could not understand.<br />\n</p>\n<p>Additionally, a 400 Bad Request\nerror was encountered while trying to use an ErrorDocument to handle the request.</p>\n<hr>\n<address>IBM_HTTP_Server at cnx65.internal Port 443</address>\n</body></html> a","v":1}
{"pid":23,"hostname":"community-suggestions-bdc8c6577-cxz5x","name":"community-suggestions/lib/server/suggestedCommunitiesService.js","level":50,"time":1583489495180,"msg":"Error while calling resolve on getCommunitiesFromAtom {}","v":1}
{"pid":23,"hostname":"community-suggestions-bdc8c6577-cxz5x","name":"community-suggestions/lib/server/boot/root.js","level":50,"time":1583489495181,"msg":"Bad XML response from Search Application: Error: Error: Unexpected close tag\nLine: 11\nColumn: 7\nChar: >","v":1}
It shows that the problem is an API request to the search /search/atom/.... Opening those link in the browser with the same CNX user specified in component pack, I get a valid XML file without any error messages.
The mentioned /home/ibm/app/lib/server/suggestedCommunitiesService.js file from the exception generates it's target API address using this function:
function getSearchRoute(res, ids) {
const restEndPoint = `/atom/mysearch?returnType=json&constraint={'type':'field','id':'id','values':${JSON.stringify(ids)},'exactMatch':true}&scope=communities:entry`;
const connectionsSearchUrl = `${process.env.CONNECTIONS_SEARCH_URL}`;
return connectionsSearchUrl + getAuthSchemeFragment(res.locals.isOauth) + restEndPoint;
}
Inside the pod, env variable CONNECTIONS_SEARCH_URL points correctly to https://cnx-ihs-host/search. Component Pack uses the request nodejs module to set a normal GET request:
request({
method: 'GET',
headers: scHeaders,
uri,
jar
}, ...
I see no reason why there should be an issue with the host header caused by this code.

Is customizer deployed? Missing header could be customizer related.
Check nginx forwarding rules, check configmap (http and https).