I am using docker-compose to start up some containers which form a cluster of Solr and Zookeeper nodes.
This is my compose file (taken from here):
version: '3.8'
services:
solr1:
image: solr:8.7.0
container_name: solr1
ports:
- "8981:8983"
environment:
- ZK_HOST=zoo1:2181,zoo2:2181,zoo3:2181
networks:
- solr
depends_on:
- zoo1
- zoo2
- zoo3
solr2:
image: solr:8.7.0
container_name: solr2
ports:
- "8982:8983"
environment:
- ZK_HOST=zoo1:2181,zoo2:2181,zoo3:2181
networks:
- solr
depends_on:
- zoo1
- zoo2
- zoo3
solr3:
image: solr:8.7.0
container_name: solr3
ports:
- "8983:8983"
environment:
- ZK_HOST=zoo1:2181,zoo2:2181,zoo3:2181
networks:
- solr
depends_on:
- zoo1
- zoo2
- zoo3
zoo1:
image: zookeeper:3.6.2
container_name: zoo1
restart: always
hostname: zoo1
ports:
- 2181:2181
- 7001:7000
environment:
ZOO_MY_ID: 1
ZOO_SERVERS: server.1=zoo1:2888:3888;2181 server.2=zoo2:2888:3888;2181 server.3=zoo3:2888:3888;2181
ZOO_4LW_COMMANDS_WHITELIST: mntr, conf, ruok
ZOO_CFG_EXTRA: "metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider metricsProvider.httpPort=7000 metricsProvider.exportJvmInfo=true"
networks:
- solr
zoo2:
image: zookeeper:3.6.2
container_name: zoo2
restart: always
hostname: zoo2
ports:
- 2182:2181
- 7002:7000
environment:
ZOO_MY_ID: 2
ZOO_SERVERS: server.1=zoo1:2888:3888;2181 server.2=zoo2:2888:3888;2181 server.3=zoo3:2888:3888;2181
ZOO_4LW_COMMANDS_WHITELIST: mntr, conf, ruok
ZOO_CFG_EXTRA: "metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider metricsProvider.httpPort=7000 metricsProvider.exportJvmInfo=true"
networks:
- solr
zoo3:
image: zookeeper:3.6.2
container_name: zoo3
restart: always
hostname: zoo3
ports:
- 2183:2181
- 7003:7000
environment:
ZOO_MY_ID: 3
ZOO_SERVERS: server.1=zoo1:2888:3888;2181 server.2=zoo2:2888:3888;2181 server.3=zoo3:2888:3888;2181
ZOO_4LW_COMMANDS_WHITELIST: mntr, conf, ruok
ZOO_CFG_EXTRA: "metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider metricsProvider.httpPort=7000 metricsProvider.exportJvmInfo=true"
networks:
- solr
networks:
solr:
If I run docker compose ls, I see that the project is correctly running:
NAME STATUS
solr-cluster running(6)
and this is the output of docker container ls:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d5333378e78c 25b74ae1e488 "docker-entrypoint.s…" 23 hours ago Up 52 minutes 0.0.0.0:8983->8983/tcp, :::8983->8983/tcp solr3
5fac27cd0443 25b74ae1e488 "docker-entrypoint.s…" 23 hours ago Up 52 minutes 0.0.0.0:8982->8983/tcp, :::8982->8983/tcp solr2
db37ef90ca98 25b74ae1e488 "docker-entrypoint.s…" 23 hours ago Up 52 minutes 0.0.0.0:8981->8983/tcp, :::8981->8983/tcp solr1
b8b55694e281 a72350516291 "/docker-entrypoint.…" 23 hours ago Up 52 minutes 2888/tcp, 3888/tcp, 8080/tcp, 0.0.0.0:2183->2181/tcp, :::2183->2181/tcp, 0.0.0.0:7003->7000/tcp, :::7003->7000/tcp zoo3
10885eafe4e8 a72350516291 "/docker-entrypoint.…" 23 hours ago Up 52 minutes 2888/tcp, 3888/tcp, 8080/tcp, 0.0.0.0:2182->2181/tcp, :::2182->2181/tcp, 0.0.0.0:7002->7000/tcp, :::7002->7000/tcp zoo2
558f8574c036 a72350516291 "/docker-entrypoint.…" 23 hours ago Up 52 minutes 2888/tcp, 3888/tcp, 0.0.0.0:2181->2181/tcp, :::2181->2181/tcp, 8080/tcp, 0.0.0.0:7001->7000/tcp, :::7001->7000/tcp zoo1
If I try to navigate a solr node with my browser using host localhost (e.g. http://localhost:8983/), the container responds correctly with the Solr Admin interface.
However, if I try to access with my browser the same container but from its IP (e.g. http://172.23.0.7:8983/, where 172.23.0.7 is the IP of solr3 container) I get a connection timeout. I also get a connection timeout if I try to ping that IP.
Why does this happen? Shouldn't both localhost and 172.23.0.7 hosts work?
I need to access my container from its IP because the Solr nodes registers to Zookeeper using their IP. So, since I can't access the containers from their IP, I get a ConnectionTimeout exception when I try to connect to them programmatically through the SolrJ APIs:
public static void main(String[] args)
{
List<String> zkNodes = new ArrayList<>(3);
zkNodes.add("localhost:2181");
zkNodes.add("localhost:2182");
zkNodes.add("localhost:2183");
SolrClient solrClient = new CloudSolrClient.Builder(zkNodes, Optional.empty())
.withConnectionTimeout(10000)
.withSocketTimeout(10000)
.build();
try
{
CollectionAdminRequest.listCollections(solrClient);
}
catch (IOException | SolrServerException e)
{
e.printStackTrace();
}
}
This is the exception I get:
org.apache.solr.client.solrj.SolrServerException: IOException occurred when talking to server at: http://172.23.0.7:8983/solr
at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:695)
at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:266)
at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:248)
at org.apache.solr.client.solrj.impl.LBSolrClient.doRequest(LBSolrClient.java:370)
at org.apache.solr.client.solrj.impl.LBSolrClient.request(LBSolrClient.java:298)
at org.apache.solr.client.solrj.impl.BaseCloudSolrClient.sendRequest(BaseCloudSolrClient.java:1157)
at org.apache.solr.client.solrj.impl.BaseCloudSolrClient.requestWithRetryOnStaleState(BaseCloudSolrClient.java:918)
at org.apache.solr.client.solrj.impl.BaseCloudSolrClient.request(BaseCloudSolrClient.java:850)
at org.apache.solr.client.solrj.SolrRequest.process(SolrRequest.java:214)
at org.apache.solr.client.solrj.SolrRequest.process(SolrRequest.java:231)
at org.apache.solr.client.solrj.request.CollectionAdminRequest.listCollections(CollectionAdminRequest.java:2690)
at Main.main(Main.java:28)
Caused by: org.apache.http.conn.ConnectTimeoutException: Connect to 172.23.0.7:8983 [/172.23.0.7] failed: connect timed out
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:151)
Caused by: org.apache.http.conn.ConnectTimeoutException: Connect to 172.23.0.7:8983 [/172.23.0.7] failed: connect timed out
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:374)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:393)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:571)
... 11 more
Caused by: java.net.SocketTimeoutException: connect timed out
Caused by: java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:75)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
... 21 more
I don't know if it that may help, but anyway I am on a Windows host, so I cannot use the --network host flag for Docker.
The 172.x.x.x IPs are IPs only reachable within the Docker network, that is between the Solr and Zookeeper nodes.
When you connect to Zookeeper from outside, Zookeeper doesn't know there is an "outside", it only knows IP of Solr servers in its network and send them back to you. But these IPs are not reachable from "outside".
One workaround can be to connect to Solr servers directly instead of using Zookeeper (with URLs like localhost:8981 and HttpSolrClient).
Or, you need to tell Solr servers to "present" themselves with the outside IP to Zookeeper.