Develop Reference

Setting up solr cloud on two machines

Enviornment - solr-8.9.0, java version "11.0.12" 2021-07-20 LTS, apache-zookeeper-3.6.1-bin/
To set-up solrCloud i have done following steps-
Setting-up Zookeeper on Node 1
a. Go inside <ZK_HOME>/conf directory.
b. Make a copy of zoo_sample.cfg & rename to zoo.cfg (or mv zoo_sample.cfg to zoo.cfg)
c. Edit zoo.cfg and modify data_dir parameter to a directory location where you would like Zookeeper to store its data.
dataDir=<ZK_HOME>/conf/data
d. Now start Zookeeper with command
./bin/zkServer.sh start
Solr Setup on Node 1 / Machine 1
a. Create directory solr-8.9.0/server/solr/node1/solr/.
b. Copy default zoo.cfg & solr.xml from solr-8.9.0/server/solr to solr5.x.x/server/solr/node1/solr/
c. Now lets start Solr using below command (basically you want to start in cloud mode with Zookeeper)
./bin/solr start -cloud -s solr-8.9.0/server/solr/node1/solr -p 8983 -z <Node1 IP>:2181 -m 2g
Solr Setup on Node 2 / Machine 2
a. Create directory solr-8.9.0/server/solr/node1/solr/.
b. Copy default zoo.cfg & solr.xml from solr-8.9.0/server/solr to solr5.x.x/server/solr/node1/solr/
c. ./solr start -cloud -s solr-8.9.0/server/solr/node1/solr -p 8983 -z <Node1 IP>:2181 -m 2g
Upload configs to Zookeeper
a. ./server/scripts/cloud-scripts/zkcli.sh -zkhost <Node1 IP>:2181 -cmd upconfig -confname _defaults -confdir solr-8.9.0/server/solr/configsets/_defaults/conf
Creating a collection
http://<Node1 IP>:8983/solr/admin/collections?action=CREATE&name=<myCollection>&numShards=2&replicationFactor=2&maxShardsPerNode=2&collection.configName=_defaults
But i am getting following error while creation of collection
{
"responseHeader":{
"status":400,
"QTime":1213},
"failure":{
"$Node2:8983_solr":"org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://$Node2:8983/solr: Path /home/solr/solr-8.9.0/server/solr/node1/solr/myCollection_shard1_replica_n2 must be relative to SOLR_HOME, SOLR_DATA_HOME coreRootDirectory. Set system property 'solr.allowPaths' to add other allowed paths.",
"$Node2:8983_solr":"org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://$Node2:8983/solr: Path /home/solr/solr-8.9.0/server/solr/node1/solr/myCollection_shard2_replica_n6 must be relative to SOLR_HOME, SOLR_DATA_HOME coreRootDirectory. Set system property 'solr.allowPaths' to add other allowed paths.",
"127.0.1.1:8983_solr":"org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://127.0.1.1:8983/solr: Path /data/Lucene/solr/solrcloud/solr-8.9.0/server/solr/node1/solr/myCollection_shard2_replica_n4 must be relative to SOLR_HOME, SOLR_DATA_HOME coreRootDirectory. Set system property 'solr.allowPaths' to add other allowed paths.",
"127.0.1.1:8983_solr":"org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException:Error from server at http://127.0.1.1:8983/solr: Path /data/Lucene/solr/solrcloud/solr-8.9.0/server/solr/node1/solr/myCollection_shard1_replica_n1 must be relative to SOLR_HOME, SOLR_DATA_HOME coreRootDirectory. Set system property 'solr.allowPaths' to add other allowed paths."},
"Operation create caused exception:":"org.apache.solr.common.SolrException:org.apache.solr.common.SolrException: Underlying core creation failed while creating collection: myCollection",
"exception":{
"msg":"Underlying core creation failed while creating collection: myCollection",
"rspCode":400},
"error":{
"metadata":[
"error-class","org.apache.solr.common.SolrException",
"root-error-class","org.apache.solr.common.SolrException"],
"msg":"Underlying core creation failed while creating collection: myCollection",
"code":400}}
Why above error was occurred? What steps i am missing while setting up solrCloud on 2 machines with 1 zookeeper instance? Could someone help me find the missing piece?

As error suggest
Use absolute path while starting the solr instance on both nodes.
Use abosolute path for 'confdir' parameter while uploading configuration to zookeeper.

AWS Elastic Beanstalk .ebextensions not updating the default configuration

I have a memory disk issue in my Elastic Beanstalk instance due to the log rotation so I am trying to modify the default configuration for log rotation by following the documentation:
https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.logging.html
After adding my config and rebuilding the environment, I can see my config (in the path which I specified) when I connect via SSH to my EB. However, it looks like my changes are not applied and logs don't rotate according to my config.
##################################################################
## Sets up the elastic beanstalk log publication to include
## the admin logs for cloudwatch logs
##################################################################
Resources:
AWSEBAutoScalingGroup:
Metadata:
"AWS::CloudFormation::Init":
configSets:
"_OnInstanceBoot":
"CmpFn::Insert":
values:
- EBCWLLogPublicationSetup
EBCWLLogPublicationSetup:
files:
"/etc/logrotate.elasticbeanstalk.hourly/logrotate.elasticbeanstalk.awslogs.conf":
content: |
/var/log/awslogs.log {
size 2M
rotate 3
missingok
compress
notifempty
copytruncate
dateext
dateformat %s
olddir /var/log/rotated
}
mode: "000644"
My EB instance contains a Java application (dropwizard, Java 1.8) which is dockerized.
Any idea?

Finally, I could find a different approach which works:
container_commands:
01-custom-rotate:
command: "/bin/sed -i 's/size 10M/size 7M/g' /etc/logrotate.elasticbeanstalk.hourly/logrotate.elasticbeanstalk.awslogs.conf"
Basically it replaces a text in the config file. The EB still needs to be rebuilt to see the changes.

neo4j keeps giving erros and is not running,can you help me with its errors?

I downloaded neo4j.zip from its site and extract it.
I downloaded and installed jdk 7, I have two folders in :
C:\Program Files\Java\jdk1.7.0_75
and
C:\Program Files\Java\jre7
And I clicked on New and made a variable named JAVA_HOME and its value is
C:\Program Files\Java\jdk1.7.0_75
I have added
org.neo4j.server.startup_timeout=0
line to my neo4j-server.properties file because of timeout error and
I have changed the port number in neo4j-server.properties file from 7474 to 80 and 8085, this is my neo4j-server.properties now:
################################################################
# Neo4j
#
# neo4j-server.properties - runtime operational settings
#
################################################################
#***************************************************************
# Server configuration
#***************************************************************
# location of the database directory
org.neo4j.server.database.location=data/graph.db
# Low-level graph engine tuning file
org.neo4j.server.db.tuning.properties=conf/neo4j.properties
# Database mode
# Allowed values:
# HA - High Availability
# SINGLE - Single mode, default.
# To run in High Availability mode, configure the neo4j.properties config file, then uncomment this line:
#org.neo4j.server.database.mode=HA
# Let the webserver only listen on the specified IP. Default is localhost (only
# accept local connections). Uncomment to allow any connection. Please see the
# security section in the neo4j manual before modifying this.
#org.neo4j.server.webserver.address=0.0.0.0
# Require (or disable the requirement of) auth to access Neo4j
dbms.security.auth_enabled=true
#
# HTTP Connector
#
# http port (for all data, administrative, and UI access)
org.neo4j.server.webserver.port=8085
#
# HTTPS Connector
#
# Turn https-support on/off
org.neo4j.server.webserver.https.enabled=true
# https port (for all data, administrative, and UI access)
org.neo4j.server.webserver.https.port=7473
# Certificate location (auto generated if the file does not exist)
org.neo4j.server.webserver.https.cert.location=conf/ssl/snakeoil.cert
# Private key location (auto generated if the file does not exist)
org.neo4j.server.webserver.https.key.location=conf/ssl/snakeoil.key
# Internally generated keystore (don't try to put your own
# keystore there, it will get deleted when the server starts)
org.neo4j.server.webserver.https.keystore.location=data/keystore
# Comma separated list of JAX-RS packages containing JAX-RS resources, one
# package name for each mountpoint. The listed package names will be loaded
# under the mountpoints specified. Uncomment this line to mount the
# org.neo4j.examples.server.unmanaged.HelloWorldResource.java from
# neo4j-server-examples under /examples/unmanaged, resulting in a final URL of
# http://localhost:7474/examples/unmanaged/helloworld/{nodeId}
#org.neo4j.server.thirdparty_jaxrs_classes=org.neo4j.examples.server.unmanaged=/examples/unmanaged
#*****************************************************************
# HTTP logging configuration
#*****************************************************************
# HTTP logging is disabled. HTTP logging can be enabled by setting this
# property to 'true'.
org.neo4j.server.http.log.enabled=false
# Logging policy file that governs how HTTP log output is presented and
# archived. Note: changing the rollover and retention policy is sensible, but
# changing the output format is less so, since it is configured to use the
# ubiquitous common log format
org.neo4j.server.http.log.config=conf/neo4j-http-logging.xml
#*****************************************************************
# Administration client configuration
#*****************************************************************
# location of the servers round-robin database directory. possible values:
# - absolute path like /var/rrd
# - path relative to the server working directory like data/rrd
# - commented out, will default to the database data directory.
org.neo4j.server.webadmin.rrdb.location=data/rrd
org.neo4j.server.startup_timeout=0
but again when I run Neo4j.bat by double clicking on it, cmd window will open and java window will open and will close after some seconds and cmd window will close after it and
http://localhost:8085/browser/
is unavailable.
This is my error from
C:\Users\Fereshteh\Desktop\neo4j-enterprise-2.2.0-windows\neo4j-enterprise-2.2.0\data\graph.db\messages
2015-04-10 01:56:42.689+0000 ERROR [o.n.s.e.EnterpriseBootstrapper]: Failed to start Neo Server on port [8085]
org.neo4j.server.ServerStartupException: Starting Neo4j Server failed: Wanted record LOG_VERSION, but this record wasn't read since the neostore didn't contain it
at org.neo4j.server.AbstractNeoServer.start(AbstractNeoServer.java:255) ~[neo4j-server-2.2.0.jar:2.2.0]
at org.neo4j.server.Bootstrapper.start(Bootstrapper.java:117) [neo4j-server-2.2.0.jar:2.2.0]
at org.neo4j.server.Bootstrapper.main(Bootstrapper.java:69) [neo4j-server-2.2.0.jar:2.2.0]
Caused by: java.lang.IllegalStateException: Wanted record LOG_VERSION, but this record wasn't read since the neostore didn't contain it
at org.neo4j.kernel.impl.store.record.NeoStoreUtil.getValue(NeoStoreUtil.java:127) ~[neo4j-kernel-2.2.0.jar:2.2.0]
at org.neo4j.kernel.impl.store.record.NeoStoreUtil.getLogVersion(NeoStoreUtil.java:150) ~[neo4j-kernel-2.2.0.jar:2.2.0]
at org.neo4j.kernel.impl.recovery.StoreRecoverer.recoveryNeededAt(StoreRecoverer.java:57) ~[neo4j-kernel-2.2.0.jar:2.2.0]
at org.neo4j.server.preflight.PerformRecoveryIfNecessary.run(PerformRecoveryIfNecessary.java:62) ~[neo4j-server-2.2.0.jar:2.2.0]
at org.neo4j.server.preflight.PreFlightTasks.run(PreFlightTasks.java:71) ~[neo4j-server-2.2.0.jar:2.2.0]
at org.neo4j.server.AbstractNeoServer.runPreflightTasks(AbstractNeoServer.java:387) ~[neo4j-server-2.2.0.jar:2.2.0]
at org.neo4j.server.AbstractNeoServer.start(AbstractNeoServer.java:195) ~[neo4j-server-2.2.0.jar:2.2.0]
And in my C:\Users\Fereshteh\Desktop\neo4j-enterprise-2.2.0-windows\neo4j-enterprise-2.2.0\data\log
I have just README and windows-wrapper.0.0.txt and windows-wrapper.0.0.log.lck
what should I do to be able to run Neo4j and work with it?
I have windows 7 x86
thanks in advance.

I had the same error today. In my case, it was because the files in the database directory were corrupted (I unzipped an existing graph which failed on first try). After I unzipped the existing graph database correctly - and the database files were fine - it worked. So, maybe your database directory is also corrupted.

Move the neo4j folder to another directory -> \Program'thisblankisbad'Files\ <- was the cause for me. I was trying to reinstall the service on Windows with
neo4j install-service
and neo4j threw:
neo4j Error: mainclass org.neo4j.server.startup.Neo4jCommand could not be found or loaded cause: java.lang.ClassNotFoundException: org.neo4j.server.startup.Neo4jCommand
after i moved the neo4j folder to another directory (NO BLANKS!!!) it was fine
windows 10, neo4j v4.4.9

How to access *.mv.db file of H2 database?

I have created database with my own program and it appeared as mydatabase.mv.db file.
But when I tried to access the same database with DbVisualizer, with apparently same parameters, it created two files mydatabase.lock.db and celebrity.h2.db and didn't see tables, created in the program.
What was the incompatibility?
UPDATE
both setups are follows:

In H2 version 1.3.x, the database file <databaseName>.h2.db is the default. (The storage engine "PageStore" is used).
In H2 version 1.4.x, the database file <databaseName>.mv.dbis the default. (The storage engine "MVStore" is used). The MVStore is still beta right now (November 2014). But you can disable the MVStore by appending ;mv_store=false to the database URL.

The accepted answer is now several years old and since others may be looking for a more "current" solution...
To get it to work just update the H2 JDBC driver that DBVizualizer uses. Basically download the "Platform-Independent Zip" from http://www.h2database.com/html/download.html and copy the h2/bin/h2-X.X.X.jar file to ~/.dbvis/jdbc/ and then restart DBVizualizer so it can pick up the updated driver.
Also, make sure you remove .mv.db from the file name when setting the Database file name in DBVizualizer.

For Windows Users:
The excellent way to read a *.db.mv file would be locally installing the h2 database and then running that database locally with the java command.
Then your path to the file will definitely show the data from your table until and unless any errors occur.
You can download the h2 database form:
http://www.h2database.com/html/download-archive.html
Note: choose the database version for H2 which supports your file.
You can install the H2 database by installing the downloaded .exe file would be around 7 MB.
then in the bin directory of H2 open a command prompt and run the command
java -jar in my case it is
command: java -jar h2-1.4.200.jar
It will show the console of the H2 database on the browser
Provide the database details:
Driver Class: org.h2.Driver JDBC
URL: jdbc:h2:~/h2 "file path"
User Name: "blank by default"
Password: "blank by default"
Refer SS below
enter image description here

How to ensure HSQLDB properties configuration loaded on Windows?

I have a problem with HSQLDB V2.3 on Windows. I can't connect with new databases using the HSQLDB Server.
Is there a log or debug option for the server so I can check the properties loaded and file paths, etc?
Is my properties file OK? I wasn't sure how to formulate file paths for windows.
Can I use quotes on file path names?
Is the connection string I'm using for the tmp db correct?
What's the correct syntax to use the --props server argument?
--props path
--props path/filename
I have set-up two environment variables (too keep it simple*). These variables don't have any effect except to save my typing. Initially I was loading the server from the HSQLDB folder directly.
HSQLDB_HOME ... home folder for the current HSQLDB
HSQLDB_DATA ... folder for data repository
I am following the the steps from:
Running and Using HSQLDB
Every time I connect via the server it makes a database called, "test" instead of letting me connect to either of the two databases specified in the server.properties.
%HSQLDB_DATA%/
test.log
test.properties
test.script
test.tmp/ .......... (folder)
test.lck
I made a 'server.properties' file in:
%HSQLDB_HOME%/lib/
where the HSQLDB JAR file is. I want two databases: tmp and dev:
# -- tmp
server.database.0=file:hsqldb/tmp_db/tmp
server.dbname.0=tmp_db
#
####
#
# -- dev
server.database.1=file:r:/.data/hsqldb/dev_db/dev
server.dbname.1=dev_db
I expected that the properties file to be enough to set-up two databases. When I run the hsqldb manager I don't get a connection for tmp say:
"jdbc:hsqldb:hsql://localhost/tmp"
user: SA, password: ""
I get a pop-up error:
database alias does not exist (Manager)
[Thread[HSQLDB Connection #26827674,5,HSQLDB Connections #372f7a8d]]: database alias=tmp does not exist (Server)
I created these two manually using the cmd-line, e.g. named "tmp":
%JAVA_HOME%\bin\java.exe -classpath %HSQLDB_HOME%\lib\hsqldb.jar org.hsqldb.server.Server org.hsqldb.server.Server --database.1 file:r:/.data/hsqldb/tmp_db --dbname.1 tmp_db
And could connect and create tmp:
%HSQLDB_DATA%/tmp_db/
tmp.log
tmp.properties
tmp.script
tmp.tmp/ .......... (folder)
tmp.lck
as forecast in the documentation. When I start-up the HSQLDB Server with the aforesaid 'server.properties' file or specifying properties explicitly:
%JAVA_HOME%\bin\java.exe -classpath %HSQLDB_HOME%\lib\hsqldb.jar org.hsqldb.server.Server --trace true --props %HSQLDB_DATA%
The server will only let me connect with a database called "test" as described at the beginning of the question.
Because the properties file looks good and the in-process file connection string works,
jdbc:hsqldb:hsqldb/tmp_db/tmp
I am left considering that the server.properties file is in the wrong place or not loading for some reason. It would be wonderful if there's a way for the server to dump the properties file at start-time :-) Thanks in advance for your suggestions ...

I have found the problem. Firstly, thanks to this tutorial:
HSQLDB Installation
After reviewing this I realised my error.
The server.properties file must be in the current folder when the server script runs. I had read that on the Running and Using HSQLDB manual page but misinterpreted its meaning and I put the properties file in my %HSQLDB_HOME%/lib folder. Oops.
When you look at the BAT script, it actually changed the current folder to be the %HSQLDB_HOME%/data folder ...
cd ..\data
So the default location for your server.properties file should be your: %HSQLDB_HOME%/data if you want to work with the default runServer.bat script.
For those wanting to separate data from the server software. I made an improvement for the default script using the two environment variables as follows.
HSQLDB_HOME ... home folder for the current HSQLDB
HSQLDB_DATA ... folder for data repository
runServer.bat:
#cd /d %HSQLDB_DATA%
#cd
#echo.
#rem __ #pause
%JAVA_HOME%\bin\java -classpath %HSQLDB_HOME%\lib\hsqldb.jar org.hsqldb.server.Server %1 %2 %3 %4 %5 %6 %7 %8 %9
#echo.
#pause
Which now expects my server.properties file in the %HSQL_DATA% folder. And that works. Also for my server since it is for development /testing, I'm using the --trace=true option. Like a lot of these things, now I get-it, it all makes perfect sense. Hopefully my misunderstanding will assist others who haven't found a simple tutorial before resorting to stackoverflow.