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linuxazurewikidatablazegraph

How do I set up remote access to a Blazegraph server?

I try to remote access my Blazegraph server, which is running on a Ubuntu VM on Azure. So I want to access the server with its public IP address, e.g. 51.123.45.234:9999. I changed the firewall settings in Azure to allow incoming traffic to port 9999, but currently I can only access the server with:

curl 127.0.0.1:9999

or

curl localhost:9999

from the ssh shell when I connect to the server. I can't even connect with the server when I try the IP of the server on the connected ssh shell.

ifconfig
eth0  Link encap:Ethernet  HWaddr 00:0d:3a:28:cd:60
      inet addr:10.0.0.4  Bcast:10.0.0.255  Mask:255.255.255.0
      inet6 addr: fe80::20d:3aff:fe28:cd60/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:208531 errors:0 dropped:328 overruns:0 frame:0
      TX packets:178597 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:170613969 (170.6 MB)  TX bytes:28500224 (28.5 MB)

lo    Link encap:Local Loopback
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:6387 errors:0 dropped:0 overruns:0 frame:0
      TX packets:6387 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1
      RX bytes:565256 (565.2 KB)  TX bytes:565256 (565.2 KB)

The IP is the one of the virtual network the VM is in and not the public one. And if I try:

curl 10.0.0.4:9999

I get:

curl: (7) Failed to connect to 10.0.0.4 port 9999: Connection refused

I set up up my server following the instructions here. I also changed my .ssh/config to:

Host queryserver
LocalForward localhost:9999 127.0.0.1:9999

I also ran netstat to check if the server is listening:

netstat -ln | grep 9999
tcp6       0      0 127.0.0.1:9999          :::*                    LISTEN

My iptables shouldn't be the problem:

sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

How can I solve this problem?

Solution

  • Wikidata-query-rdf starts jetty servlet container and installs blazegraph-service-*.war, note that it specifies --host $HOST, which defaults to 'localhost' in runBlazegraph.sh script.

    According to Jetty configuration, if --host specified, it defines the interface to listen on, so by default Blazegraph run by Wikidata-query-rdf listens only to localhost interface.

    Specify -h your_ip while running runBlazegraph.sh :

    ./runBlazegraph.sh -h 10.0.0.4

    If that does not resolve the issue, you might need to use 0.0.0.0 host name to listen on all interfaces and enable preferred IPv4 stack for java):

    ./runBlazegraph.sh -h 0.0.0.0 -o -Djava.net.preferIPv4Stack=true