我正在尝试将外部应用程序连接到在Mesos群集上运行dockerized的Cassandra。
这些是我在mesos上运行的应用程序：
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
137760ce852a cassandra:latest "/docker-entrypoint.s" 15 minutes ago Up 15 minutes 7000-7001/tcp, 7199/tcp, 9160/tcp, 0.0.0.0:31634->9042/tcp mesos-1b65f33a-3d36-4bf4-8a77-32077d8d234a-S1.0db174cc-2e0c-4790-9cd7-1f142d08c6e2
fec5fc93ccfd cassandra:latest "/docker-entrypoint.s" 22 minutes ago Up 22 minutes 7000-7001/tcp, 7199/tcp, 9160/tcp, 0.0.0.0:31551->9042/tcp mesos-1b65f33a-3d36-4bf4-8a77-32077d8d234a-S1.0022a3d2-d695-43c4-b22f-f5274cbd03ce
ca729ee628bb tobilg/mesos-dns "./bootstrap.sh" About an hour ago Up About an hour mesos-1b65f33a-3d36-4bf4-8a77-32077d8d234a-S1.12593777-2295-42fa-a56d-1d3cc9fc70ff
3921002a8a5b python:3 "/bin/sh -c 'env >env" About an hour ago Up About an hour 0.0.0.0:31295->8080/tcp mesos-1b65f33a-3d36-4bf4-8a77-32077d8d234a-S1.b101ab59-2538-416f-80cf-29215794bd37
名为 peek 的应用程序仅用于测试提案。我可以通过网址http://192.168.56.101:10001访问它，没有任何问题。
2个cassandra实例是种子，另一个用于扩展;形成一个集群。
在马拉松上部署cassandra应用程序的json描述如下：
/卡桑德拉种子
{
"id": "cassandra-seed",
"constraints": [["hostname", "CLUSTER", "docker-sl-vm"]],
"container": {
"type": "DOCKER",
"docker": {
"image": "cassandra:latest",
"network": "BRIDGE",
"portMappings": [ {"containerPort": 9042,"hostPort": 0,"servicePort": 0,"protocol": "tcp"} ]
}
},
"cpus": 0.5,
"mem": 512.0,
"instances": 1,
"backoffSeconds": 1,
"backoffFactor": 1.15,
"maxLaunchDelaySeconds": 3600
}
/卡桑德拉
{
"id": "cassandra",
"constraints": [["hostname", "CLUSTER", "docker-sl-vm"]],
"container": {
"type": "DOCKER",
"docker": {
"image": "cassandra:latest",
"network": "BRIDGE",
"portMappings": [ {"containerPort": 9042,"hostPort": 0,"servicePort": 0,"protocol": "tcp"} ]
}
},
"env": {
"CASSANDRA_SEED_COUNT": "1",
"CASSANDRA_SEEDS": "cassandra-seed.marathon.mesos"
},
"cpus": 0.5,
"mem": 512.0,
"instances": 1,
"backoffSeconds": 1,
"backoffFactor": 1.15,
"maxLaunchDelaySeconds": 3600
}
haproxy配置如下：
global
daemon
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
maxconn 4096
tune.ssl.default-dh-param 2048
defaults
log global
retries 3
maxconn 2000
timeout connect 5s
timeout client 50s
timeout server 50s
listen stats
bind 127.0.0.1:9090
balance
mode http
stats enable
stats auth admin:admin
frontend marathon_http_in
bind *:80
mode http
frontend marathon_http_appid_in
bind *:81
mode http
frontend marathon_https_in
bind *:443 ssl crt /etc/ssl/xip.io/xip.io.pem
mode http
frontend cassandra_10003
bind *:10003
mode tcp
use_backend cassandra_10003
frontend cassandra-seed_10002
bind *:10002
mode tcp
use_backend cassandra-seed_10002
frontend dns_10000
bind *:10000
mode tcp
use_backend dns_10000
frontend peek_10001
bind *:10001
mode tcp
use_backend peek_10001
backend cassandra_10003
balance roundrobin
mode tcp
server docker-sl-vm_31634 192.168.56.102:31634
backend cassandra-seed_10002
balance roundrobin
mode tcp
server docker-sl-vm_31551 192.168.56.102:31551
backend dns_10000
balance roundrobin
mode tcp
server docker-sl-vm_31314 192.168.56.102:31314
backend peek_10001
balance roundrobin
mode tcp
server docker-sl-vm_31295 192.168.56.102:31295
我尝试连接到Cassandra的应用程序是一个Play应用程序。我这样设置：
akka.persistence {
journal.plugin = "cassandra-journal"
snapshot-store.plugin = "cassandra-snapshot-store"
}
cassandra-journal.contact-points = ["192.168.56.101:10003"]
cassandra-snapshot-store.contact-points = ["192.168.56.101:10003"]
该应用程序启动正常，但当我尝试访问它时，我收到以下错误：
! @6o380dcg9 - Internal server error, for (GET) [/issues/list] ->
play.api.Application$$anon$1: Execution exception[[TimeoutException: deadline passed]]
at play.api.Application$class.handleError(Application.scala:296) ~[play_2.11-2.3.10.jar:2.3.10]
at play.api.DefaultApplication.handleError(Application.scala:402) [play_2.11-2.3.10.jar:2.3.10]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:205) [play_2.11-2.3.10.jar:2.3.10]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$14$$anonfun$apply$1.applyOrElse(PlayDefaultUpstreamHandler.scala:202) [play_2.11-2.3.10.jar:2.3.10]
at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:36) [scala-library-2.11.7.jar:na]
Caused by: java.util.concurrent.TimeoutException: deadline passed
at akka.actor.dsl.Inbox$InboxActor$$anonfun$receive$1.applyOrElse(Inbox.scala:117) ~[akka-actor_2.11-2.4.0.jar:na]
at scala.PartialFunction$AndThen.applyOrElse(PartialFunction.scala:189) ~[scala-library-2.11.7.jar:na]
at akka.actor.Actor$class.aroundReceive(Actor.scala:480) ~[akka-actor_2.11-2.4.0.jar:na]
at akka.actor.dsl.Inbox$InboxActor.aroundReceive(Inbox.scala:62) ~[akka-actor_2.11-2.4.0.jar:na]
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:525) ~[akka-actor_2.11-2.4.0.jar:na]
[error] c.d.d.c.Session - Error creating pool to /172.17.0.2:9042
com.datastax.driver.core.TransportException: [/172.17.0.2:9042] Cannot connect
at com.datastax.driver.core.Connection.<init>(Connection.java:109) ~[cassandra-driver-core-2.1.5.jar:na]
at com.datastax.driver.core.PooledConnection.<init>(PooledConnection.java:32) ~[cassandra-driver-core-2.1.5.jar:na]
at com.datastax.driver.core.Connection$Factory.open(Connection.java:586) ~[cassandra-driver-core-2.1.5.jar:na]
at com.datastax.driver.core.SingleConnectionPool.<init>(SingleConnectionPool.java:76) ~[cassandra-driver-core-2.1.5.jar:na]
at com.datastax.driver.core.HostConnectionPool.newInstance(HostConnectionPool.java:35) ~[cassandra-driver-core-2.1.5.jar:na]
Caused by: org.jboss.netty.channel.ConnectTimeoutException: connection timed out: /172.17.0.2:9042
at org.jboss.netty.channel.socket.nio.NioClientBoss.processConnectTimeout(NioClientBoss.java:139) ~[netty-3.9.9.Final.jar:na]
at org.jboss.netty.channel.socket.nio.NioClientBoss.process(NioClientBoss.java:83) ~[netty-3.9.9.Final.jar:na]
at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337) ~[netty-3.9.9.Final.jar:na]
at org.jboss.netty.channel.socket.nio.NioClientBoss.run(NioClientBoss.java:42) ~[netty-3.9.9.Final.jar:na]
at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) ~[netty-3.9.9.Final.jar:na]
[error] c.d.d.c.Session - Error creating pool to /172.17.0.2:9042
有谁知道如何解决这个问题？我做错了什么？
提前谢谢你......
更新=============================
有趣的是我的应用程序的键空间已创建（akka，akka_snapshots）：
cqlsh> describe keyspaces;
akka_snapshot system_auth system system_distributed system_traces akka
更新2 =============================
我刚刚注意到我甚至无法将应用程序直接连接到正在运行的cassandra（无需通过haproxy）。所以，我已将portMapping更改为：
"portMappings": [ {"containerPort": 9042,"hostPort": 0,"servicePort": 9042,"protocol": "tcp"} ]
它有效。 HOWEVER ，由于servicePort声明，它只允许我启动一台机器。
问题在于端口映射。任何线索？
答案 0 :(得分：2)
我了解到您正在使用haproxy进行Cassandra群集的服务发现。如果是这样，如果您没有一个机制来更新配置，一旦Marathon中的任务发生更改（缩放等），它就不会成功。
Cassandra节点无法相互通信的问题可能是/cassandra应用没有引用/cassandra-seed。
根据Cassandra Docker image docs，您应该可以动态配置CASSANDRA_SEEDS env参数。
为了能够使用服务名称cassandra-seed.marathon.mesos，如果有必要将其解析为IP地址首先恕我直言：
"CASSANDRA_SEEDS": "$(host cassandra-seed.marathon.mesos | awk '/has address/ { print $4 }')"
理论上工作（例如，如果您的应用只有一个实例）。
由于您似乎使用Mesos DNS，可能会出现问题，因为当前（v0.4.0）仅公布了内部IP地址（请参阅Issue）。您可能不得不回到“真正的”Mesos DNS客户端，该客户端可以解析SRV记录以正确地将这些记录映射到Mesos Slave IP地址和端口。
或者，您可以自己解析dig结果并将其用作CASSANDRA_SEEDS env参数的输入：
dig _cassandra-seed._tcp.marathon.mesos SRV
请参阅Mesos DNS docs。
mesosdns-cli可以处理这个问题，但需要在Docker容器中使用Node.js运行时。因此，您必须创建自己的cassandra Docker图像派生。