[jira] [Updated] (KNOX-1165) Knox - Another unnamed CacheManager already exists in the same VM.

["Kevin Risden (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KNOX-1165?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kevin Risden updated KNOX-1165:
-------------------------------
    Labels:   (was: patch)

> Knox - Another unnamed CacheManager already exists in the same VM.
> ------------------------------------------------------------------
>
>                 Key: KNOX-1165
>                 URL: https://issues.apache.org/jira/browse/KNOX-1165
>             Project: Apache Knox
>          Issue Type: Bug
>          Components: KnoxSSO, Server
>    Affects Versions: 0.12.0
>         Environment: JDK 1.8
> CentOS-6 (64bit)
>            Reporter: Ernani Pereira de Mattos Junior
>            Priority: Critical
>             Fix For: 1.2.0
>
>
> *Problem*
> Issue is described on the note "Error:Shiro environment initialization failed" when starting KNOX;
> {code:java}
> ERROR env.EnvironmentLoader (EnvironmentLoader.java:initEnvironment(146)) - Shiro environment initialization failed
>  org.apache.shiro.cache.CacheException: net.sf.ehcache.CacheException: Another unnamed CacheManager already exists in the same VM. Please provide unique names for each CacheManager in the config or do one of following {code}
> After implementing the solution of creating a new ehcache.xml and reference as <ehcache name="knox-mytopology1"> we still see the issue:
> {code:java}
> Caused by: net.sf.ehcache.CacheException: Another CacheManager with same name 'knox-tp' already exists in the same VM. Please provide unique names for each CacheManager in the config or do one of following: {code}
> *Steps to reproduce*
> When enabling the following parameters: 
> {code:java}
> <param>
>   <name>main.cacheManager</name>
>   <value>org.apache.shiro.cache.ehcache.EhCacheManager</value>
> </param>
> <param>
>   <name>main.securityManager.cacheManager</name>
>   <value>$cacheManager</value>
> </param>
> <param>
>   <name>main.ldapRealm.authenticationCachingEnabled</name>
>   <value>true</value>
> </param>{code}
> *More Info*
> This KNOX-804 was open to solve this same issue but is not documented anywhere, but we can see the coding changes in GitHub.
>  * The issue seems to be a racing condition on the Shiro lib class, in which depending on the processing power of the server there are two threads within the same "if" statement;
>  ** ref: [https://github.com/apache/shiro/blob/master/support/ehcache/src/main/java/org/apache/shiro/cache/ehcache/EhCacheManager.java]
>  * The Default constructor only builds the Object, and does not do much: 
>  * 
> {code:java}
> /**Default no argument constructor*/
>  public EhCacheManager() {
>  }{code}
>  * Accordingly with shiro documentation: 
>  ** 
> {code:java}
> /**
> Initializes this instance.
> <p/>
> If a {@link #setCacheManager CacheManager} has been explicitly set (e.g. via Dependency Injection or programmatically) prior to calling this
> method, this method does nothing.
> <p/>
> However, if no {@code CacheManager} has been set, the default Ehcache singleton will be initialized, where Ehcache will look for an {@code ehcache.xml} file at the root of the classpath. If one is not found, Ehcache will use its own failsafe configuration file.
> <p/>
> Because Shiro cannot use the failsafe defaults (fail-safe expunges cached objects after 2 minutes, something not desirable for Shiro sessions), this class manages an internal default configuration for this case.
> @throws org.apache.shiro.cache.CacheException if there are any CacheExceptions thrown by EhCache.
> @see net.sf.ehcache.CacheManager#create
>  */
> public final void init() throws CacheException { ensureCacheManager(); }
> private net.sf.ehcache.CacheManager ensureCacheManager()
> { ***It fails in here. }{code}
>  * This is the head of the exception: The source of the existing CacheManager is:
>  ** 
> {code:java}
> InputStreamConfigurationSource [stream=java.io.BufferedInputStream@675ffd1d] at org.apache.shiro.cache.ehcache.EhCacheManager.ensureCacheManager(EhCacheManager.java:224) at org.apache.shiro.cache.ehcache.EhCacheManager.init(EhCacheManager.java:199) at org.apache.shiro.util.LifecycleUtils.init(LifecycleUtils.java:45) at org.apache.shiro.util.LifecycleUtils.init(LifecycleUtils.java:40){code}
>  * Starting from KNOX-804, the KnoxCacheManager was introduced. Remember that Init() will do nothing if anything in case the setCacheManager is explicitly set.
>  ** ref: [https://github.com/apache/knox/commit/f9d8e07d768459240c8665f139cc140575dc5216]



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