so what i tried:
curl "http://localhost:5601/api/saved_objects/index-pattern/2081fa30-0021-11e8-986a-11b6eea8e9ce" > ip.json
this will export my index pattern to ip.json, which looks like this:
{"id":"2081fa30-0021-11e8-986a-11b6eea8e9ce","type":"index-pattern","updated_at":"2018-01-23T09:38:12.340Z","version":2,"attributes":{"title":"exception_index","fields":"[{\"name\":\"Date&Time\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Level\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Message.ExceptionList\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Message.Root\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Tags\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Title\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_id\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false},{\"name\":\"_index\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false},{\"name\":\"_score\",\"type\":\"number\",\"count\":0,\"scripted\":false,\"searchable\":false,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_source\",\"type\":\"_source\",\"count\":0,\"scripted\":false,\"searchable\":false,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_type\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false}]"}}
now i just remove the id, type,updated_at and version (i don't change anything else):
{"attributes":{"title":"exception_index","fields":"[{\"name\":\"Date&Time\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Level\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Message.ExceptionList\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Message.Root\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Tags\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"Title\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_id\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false},{\"name\":\"_index\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false},{\"name\":\"_score\",\"type\":\"number\",\"count\":0,\"scripted\":false,\"searchable\":false,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_source\",\"type\":\"_source\",\"count\":0,\"scripted\":false,\"searchable\":false,\"aggregatable\":false,\"readFromDocValues\":false},{\"name\":\"_type\",\"type\":\"string\",\"count\":0,\"scripted\":false,\"searchable\":true,\"aggregatable\":true,\"readFromDocValues\":false}]"}}
and then import with:
curl -X POST 'http://localhost:5601/hga/api/saved_objects/index-pattern/' -H 'Content-Type: application/json' -H "kbn-xsrf: true" -d "@ip.json"
which works as expected