Merge branch 'master' of https://github.com/yacy/yacy_net_homepage

docs/dev/solr.md

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+# Solr and YaCy Integration
+
+Hint: If you are not a developer, just don't care about this topic. Solr
+is already inside YaCy, just do nothing.
+
+YaCy uses Solr (and other data structures) to store the local search
+index (while the remote search index is a RWI data structure). The Solr
+index is deeply/programmatically embedded into YaCy, but it is also
+possible to use an external Solr index which can then be assigned to
+YaCy as external storage. This can be activated with one single click if
+you have a running Solr, configured for YaCy.
+
+The remote index scheme is similar (but extended) to SolrCell; see
+<http://wiki.apache.org/solr/ExtractingRequestHandler> We added some
+more generic fields, added a second solr core and therefore we need to
+use the solr.xml and schema.xml from a YaCy installation.
+
+## Use the deep-embedded Solr in YaCy and an external Solr concurrently
+
+This is the default setting. The assignment of a remote Solr and also
+switching off of the embedded Solr is done in the servlet
+/IndexFederated_p.html. The embedded Solr is switched on, if the flag
+"Use deep-embedded local Solr" is switched on.
+
+## Use an external Solr or Solr Shards to have a distributed Solr-backend for a single YaCy
+
+In the "Solr URL(s)" field of the
+<http://localhost:8090/IndexFederated_p.html> servlet, you can enter
+several Solr addresses. If there is more than one Solr assigned, these
+are accessed as a 'Shard'. This will cause that each document is hashed
+using the document id and stored only in one of the shards. If a query
+to Solr is made, then all shards are queried concurrently and the
+results are merged.
+
+## Concurrent usage of the embedded Solr and an external Solr or Solr Shard
+
+It is possible to leave the "Use deep-embedded local Solr" flag switched
+on while using an external Solr. Then each document is stored in the
+local and the remote Solr. If a document is searched, this is done
+concurrently in the local and remote Solr as if they are a Solr Shard.
+
+# How to deploy an external Solr for YaCy
+
+The deployment needs two steps: (1) embedd Solr into a servlet
+environment, (2) configure Solr for YaCy. Both is described in each of
+the following three options: you can choose between Jetty and Tomcat as
+servlet container, do only one of the following three:
+
+## Use the example-deployment in a Solr package
+
+This is probably the easiest and fastest way to test a YaCy-Solr
+connection. Don't do this for a production environment; one of the next
+two options is better for this. The following steps uses Solr 4.1.0; you
+can use the most recent version as well.
+
+  - Download solr-4.1.0.tgz from <http://lucene.apache.org/solr/>
+  - Decompress solr-4.1.0.tgz (with 'tar xfz solr-4.1.0.tgz') and put
+    solr-4.1.0 into ~/
+  - We must defined two cores for Solr: the default collection1 and an
+    addition 'webgraph' core. This is done by copying the YaCy solr.xml
+
+<!-- end list -->
+
+    cp ~/yacy/defaults/solr/solr.xml ~/solr-4.1.0/example/solr/collection1/conf/
+
+  - The webgraph core is basically a copy of the default collection1
+    core. Create a configuration for the webgraph as a clone of
+    collection1:
+
+<!-- end list -->
+
+    mkdir ~/solr-4.1.0/example/solr/webgraph
+    cp -R ~/solr-4.1.0/example/solr/collection1/conf ~/solr-4.1.0/example/solr/webgraph/conf
+
+  - A YaCy schema configuration must be copied to each core. To do this,
+    we have two options: either copy a generic version of the schema.xml
+    as used by YaCy
+
+<!-- end list -->
+
+    cp ~/yacy/defaults/solr/schema.xml ~/solr-4.1.0/example/solr/collection1/conf/
+    cp ~/yacy/defaults/solr/schema.xml ~/solr-4.1.0/example/solr/webgraph/conf/
+
+or, using the explicit schema definition which can be extracted from the
+YaCy API; start YaCy (if not already running) and execute the following
+commands:
+
+    ~/yacy/bin/apicat.sh /api/schema.xml?core=collection1 > ~/solr-4.1.0/example/solr/collection1/conf/schema.xml
+    ~/yacy/bin/apicat.sh /api/schema.xml?core=webgraph > ~/solr-4.1.0/example/solr/webgraph/conf/schema.xml
+
+  - Finally, start the external Solr with:
+
+<!-- end list -->
+
+    cd ~/solr-4.1.0/example/ && java -jar start.jar
+
+Solr is then running at <http://127.0.0.1:8983/solr>
+
+  - Start YaCy (if not already running) and open
+    <http://localhost:8090/IndexFederated_p.html>
+  - in the "Solr URL(s)" field, enter: <http://127.0.0.1:8983/solr> (or
+    a remote address, if you want to run solr on a different server)
+  - uncheck the "Use deep-embedded local Solr" flag and check the "Use
+    remote Solr server(s)" flag
+
+## Deploy Solr in Tomcat
+
+First you must download and decompress tomcat 6. In this example you
+install tomcat to your home directory at `~/tomcat/`
+
+    cd ~
+    wget http://archive.apache.org/dist/tomcat/tomcat-6/v6.0.37/bin/apache-tomcat-6.0.37.tar.gz
+    tar xfz apache-tomcat-6.0.37.tar.gz
+    mv apache-tomcat-6.0.37 tomcat
+
+To deploy a solr container, download a solr package and copy the
+relevant files to the correct tomcat subdirectory:
+
+    cd ~/tomcat
+    wget http://www.eu.apache.org/dist/lucene/solr/4.5.1/solr-4.5.1.tgz
+    tar xfz solr-4.5.1.tgz
+    cp solr-4.5.1/dist/solr-4.5.1.war .
+    cp -R solr-4.5.1/example/solr yacyindex
+
+We need to copy the YaCy schema and the definition of the second core
+'webgraph'. Consider that at ~/yacy you have installed a YaCy peer,
+then you can simply copy the generic schema file for collection1 to
+solr:
+
+    cp ~/yacy/defaults/solr/schema.xml ~/tomcat/yacyindex/collection1/conf/
+
+Clone the collection1 to get the webgraph core
+
+    cp -R ~/tomcat/yacyindex/collection1 ~/tomcat/yacyindex/webgraph
+
+Patch the core.properties in
+`~/tomcat/yacyindex/webgraph/core.properties` and replace the line
+`name=collection1` with `name=webgraph`. Then copy the solr.xml
+definition for two cores:
+
+    cp ~/yacy/defaults/solr/solr.xml ~/tomcat/yacyindex/
+
+Copy the solr logging libraries to the tomcat library folder because
+Solr uses a different logging in jetty as implemented in solr. In the
+~/tomcat directory, do
+
+    cp solr-4.5.1/example/lib/ext/* ~/tomcat/lib/
+
+To deploy Solr with the YaCy configuration you must create a Tomcat
+Context fragment. This is a file within the conf subdirecty which is
+created once tomcat was started. Therefore we start tomcat now:
+
+    ~/tomcat/bin/startup.sh
+
+Look at the path `~/tomcat/conf/Catalina/localhost` which was now
+created. Thats the place where we create the Tomcat Context fragment.
+You need the absolute path to the tomcat installation directory which we
+consider as `/home/administrator/tomcat` in this example. Create a file in
+`/home/administrator/tomcat/conf/Catalina/localhost/solr4yacy.xml` with
+the following content:
+
+    <?xml version="1.0" encoding="utf-8"?>
+    <Context docBase="/home/administrator/tomcat/solr-4.5.1.war" debug="0" crossContext="true">
+      <Environment name="solr/home" type="java.lang.String" value="/home/administrator/tomcat/yacyindex" override="true"/>
+    </Context>
+
+Restart tomcat to activate this configuration
+
+    ~/tomcat/bin/shutdown.sh && ~/tomcat/bin/startup.sh
+
+Finished! You can now access Solr with the url
+<http://localhost:8080/solr4yacy/> This is the url which you can set in
+the "Use remote Solr server(s)" field of the /IndexFederated_p.html
+servlet in YaCy to attach the solr-in-tomcat to YaCy as remote storage
+server. When doing this you may want to remove the flag "Use
+deep-embedded local Solr" so this remote solr becomes the single storage
+point for the YaCy search index.
+
+### User Administration and Search Index Access Protection
+
+Tomcat can add a password protection to web pages. There is i.e. a
+default manager web application available at
+<http://localhost:8080/manager/html> which cannot be accessed without
+setting a role and a user name for this. We will activate the manager to
+test the password protection: write the new role "manager" to the file
+`~/tomcat/conf/tomcat-users.xml` and set a password, i.e.
+
+    <?xml version='1.0' encoding='utf-8'?>
+    <tomcat-users>
+      <role rolename="manager"/>
+      <user username="admin" password="tomcat" roles="manager"/>
+    </tomcat-users>
+
+Re-start tomcat, then open <http://localhost:8080/manager/html> and
+manage solr applications there. Log-in with the user name 'admin' and
+the password 'tomcat'. We will use this now to access our YaCy search
+index in Solr. To do this, we need access rules defined in the web.xml
+configuration file to declare a role to be protected. We will call this
+role 'user' and the paths to be all paths within tomcat. Open the file
+`~/tomcat/conf/web.xml` and add the following lines at the end before the
+closing tag \</web-app\>:
+
+    <security-constraint>
+        <web-resource-collection>
+            <url-pattern>/*</url-pattern>
+        </web-resource-collection>
+        <auth-constraint>
+            <role-name>user</role-name>
+        </auth-constraint>
+    </security-constraint>
+    <login-config>
+        <auth-method>BASIC</auth-method>
+        <realm-name>tomcat</realm-name>
+    </login-config>
+    <security-role>
+        <role-name>user</role-name>
+    </security-role>
+
+To use the new role 'user', we add an account in the file
+`~/tomcat/conf/tomcat-users.xml`. Add the following lines to
+\<tomcat-users\>:
+
+``` 
+  <role rolename="user"/>
+  <user username="yacyadmin" password="yacy123" roles="user"/>
+```
+
+and restart tomcat. You can now access Solr with the url
+<http://yacyadmin:yacy123@localhost:8080/solr4yacy/> This is the url
+which you can set in the "Use remote Solr server(s)" field of the
+/IndexFederated_p.html servlet in YaCy. The account:password encoding
+in the url is used by YaCy to access the solr index within tomcat.
+
+# Copy the deeply-embedded Solr Index to an external Solr
+
+This is easy, just copy the Solr directory in
+DATA/INDEX/\<network\>/SEGMENTS/solr\_40 into the solr data directory of
+your remote Solr installation. You can also do this using a script
+during runtime. Call
+
+    ~/yacy/bin/indexdump.sh
+
+which causes that YaCy creates a tar.gz file of the `solr_40` directory
+during runtime and the indexdump.sh script returns the file path to this
+tar.gz file. This filename can then be processed further with your own
+copy-and-deploy script to fill a remote Solr with that.
+
+
+
+For cluster solr usage, see [Solr Cloud instructions](./solrcloud.md)
+
+
+_Converted from
+<https://wiki.yacy.net/index.php?title=Dev:Solr>, may be outdated_
+
+
+
+