--- layout: default title: Cross-Cluster Search parent: Access Control grand_parent: Security nav_order: 40 --- # Cross-cluster search Cross-cluster search is exactly what it sounds like: it lets any node in a cluster execute search requests against other clusters. The security plugin supports cross-cluster search out of the box. --- #### Table of contents 1. TOC {:toc} --- ## Authentication flow When accessing a *remote cluster* from a *coordinating cluster* using cross-cluster search: 1. The security plugin authenticates the user on the coordinating cluster. 1. The security plugin fetches the user's backend roles on the coordinating cluster. 1. The call, including the authenticated user, is forwarded to the remote cluster. 1. The user's permissions are evaluated on the remote cluster. You can have different authentication and authorization configurations on the remote and coordinating cluster, but we recommend using the same settings on both. ## Permissions To query indices on remote clusters, users need to have the following permissions for the index, in addition to `READ` or `SEARCH` permissions: ``` indices:admin/shards/search_shards ``` #### Sample roles.yml configuration ```yml humanresources: cluster: - CLUSTER_COMPOSITE_OPS_RO indices: 'humanresources': '*': - READ - indices:admin/shards/search_shards # needed for CCS ``` #### Sample role in OpenSearch Dashboards ![OpenSearch Dashboards UI for creating a cross-cluster search role](../../../images/security-ccs.png) ## Walkthrough Save this file as `docker-compose.yml` and run `docker-compose up` to start two single-node clusters on the same network: ```yml version: '3' services: opensearch-node1: image: opensearch/opensearch:{{site.opensearch_version}} container_name: opensearch-node1 environment: - cluster.name=opensearch-cluster1 - discovery.type=single-node - bootstrap.memory_lock=true # along with the memlock settings below, disables swapping - "ES_JAVA_OPTS=-Xms512m -Xmx512m" # minimum and maximum Java heap size, recommend setting both to 50% of system RAM ulimits: memlock: soft: -1 hard: -1 volumes: - opensearch-data1:/usr/share/opensearch/data ports: - 9200:9200 - 9600:9600 # required for Performance Analyzer networks: - opensearch-net opensearch-node2: image: opensearch/opensearch:{{site.opensearch_version}} container_name: opensearch-node2 environment: - cluster.name=opensearch-cluster2 - discovery.type=single-node - bootstrap.memory_lock=true # along with the memlock settings below, disables swapping - "ES_JAVA_OPTS=-Xms512m -Xmx512m" # minimum and maximum Java heap size, recommend setting both to 50% of system RAM ulimits: memlock: soft: -1 hard: -1 volumes: - opensearch-data2:/usr/share/opensearch/data ports: - 9250:9200 - 9700:9600 # required for Performance Analyzer networks: - opensearch-net volumes: opensearch-data1: opensearch-data2: networks: opensearch-net: ``` After the clusters start, verify the names of each: ```json curl -XGET -u 'admin:admin' -k 'https://localhost:9200' { "cluster_name" : "opensearch-cluster1", ... } curl -XGET -u 'admin:admin' -k 'https://localhost:9250' { "cluster_name" : "opensearch-cluster2", ... } ``` Both clusters run on `localhost`, so the important identifier is the port number. In this case, use port 9200 (`opensearch-node1`) as the remote cluster, and port 9250 (`opensearch-node2`) as the coordinating cluster. To get the IP address for the remote cluster, first identify its container ID: ```bash docker ps CONTAINER ID IMAGE PORTS NAMES 6fe89ebc5a8e opensearch/opensearch:{{site.opensearch_version}} 0.0.0.0:9200->9200/tcp, 0.0.0.0:9600->9600/tcp, 9300/tcp opensearch-node1 2da08b6c54d8 opensearch/opensearch:{{site.opensearch_version}} 9300/tcp, 0.0.0.0:9250->9200/tcp, 0.0.0.0:9700->9600/tcp opensearch-node2 ``` Then get that container's IP address: ```bash docker inspect --format='{% raw %}{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}{% endraw %}' 6fe89ebc5a8e 172.31.0.3 ``` On the coordinating cluster, add the remote cluster name and the IP address (with port 9300) for each "seed node." In this case, you only have one seed node: ```json curl -k -XPUT -H 'Content-Type: application/json' -u 'admin:admin' 'https://localhost:9250/_cluster/settings' -d ' { "persistent": { "search.remote": { "opensearch-cluster1": { "seeds": ["172.31.0.3:9300"] } } } }' ``` On the remote cluster, index a document: ```bash curl -XPUT -k -H 'Content-Type: application/json' -u 'admin:admin' 'https://localhost:9200/books/_doc/1' -d '{"Dracula": "Bram Stoker"}' ``` At this point, cross-cluster search works. You can test it using the `admin` user: ```bash curl -XGET -k -u 'admin:admin' 'https://localhost:9250/opensearch-cluster1:books/_search?pretty' { ... "hits": [{ "_index": "opensearch-cluster1:books", "_type": "_doc", "_id": "1", "_score": 1.0, "_source": { "Dracula": "Bram Stoker" } }] } ``` To continue testing, create a new user on both clusters: ```bash curl -XPUT -k -u 'admin:admin' 'https://localhost:9200/_opensearch/_security/api/internalusers/booksuser' -H 'Content-Type: application/json' -d '{"password":"password"}' curl -XPUT -k -u 'admin:admin' 'https://localhost:9250/_opensearch/_security/api/internalusers/booksuser' -H 'Content-Type: application/json' -d '{"password":"password"}' ``` Then run the same search as before with `booksuser`: ```json curl -XGET -k -u booksuser:password 'https://localhost:9250/opensearch-cluster1:books/_search?pretty' { "error" : { "root_cause" : [ { "type" : "security_exception", "reason" : "no permissions for [indices:admin/shards/search_shards, indices:data/read/search] and User [name=booksuser, roles=[], requestedTenant=null]" } ], "type" : "security_exception", "reason" : "no permissions for [indices:admin/shards/search_shards, indices:data/read/search] and User [name=booksuser, roles=[], requestedTenant=null]" }, "status" : 403 } ``` Note the permissions error. On the remote cluster, create a role with the appropriate permissions, and map `booksuser` to that role: ```bash curl -XPUT -k -u 'admin:admin' -H 'Content-Type: application/json' 'https://localhost:9200/_opensearch/_security/api/roles/booksrole' -d '{"index_permissions":[{"index_patterns":["books"],"allowed_actions":["indices:admin/shards/search_shards","indices:data/read/search"]}]}' curl -XPUT -k -u 'admin:admin' -H 'Content-Type: application/json' 'https://localhost:9200/_opensearch/_security/api/rolesmapping/booksrole' -d '{"users" : ["booksuser"]}' ``` Both clusters must have the user, but only the remote cluster needs the role and mapping; in this case, the coordinating cluster handles authentication (i.e. "Does this request include valid user credentials?"), and the remote cluster handles authorization (i.e. "Can this user access this data?"). {: .tip } Finally, repeat the search: ```bash curl -XGET -k -u booksuser:password 'https://localhost:9250/opensearch-cluster1:books/_search?pretty' { ... "hits": [{ "_index": "opensearch-cluster1:books", "_type": "_doc", "_id": "1", "_score": 1.0, "_source": { "Dracula": "Bram Stoker" } }] } ```