I am getting following error while running the cassandra.
$ sudo service cassandra start
$ cassandra
Java HotSpot(TM) Server VM warning: Cannot open file /var/log/cassandra/gc.log due to Permission denied.
I guess you have installed the Cassandra using repositories. Cassandra needs a directory to store data and in your case, it cannot create that directories because of permission problems. You have three-way:
Become the root user using the command sudo su and run the command cassandra as the root user. You can issue the command sudo systemctl enable cassandra.service to run Cassandra automatically at startup.
change the following setting in cassandra.yaml file to where the user has permission, like your home directory.
data_file_directories
commitlog_directory
saved_caches_directory
add the line export CASSANDRA_HOME=path/to/cassandra in user .bashrc file and after that run source .bashrc to compile it. This makes Cassandra know the Cassandra install directory and creates the nesseccery folder within that.
Related
In some beta version of Arangodb 3.4 my database crashed while I tried to add a view via arangosh. Because I were not able to start the database anymore, it was not possible to make a backup (database dump).
I just wanted to install the newest Arangodb 3.4.2.1 then, but that failed because my CPU was to old (no SSE 4.2 support). So I bought a new computer, sat up a new linux, copied the databases to /var/lib/arangodb3/databases, started a new installation of Arangodb in which it even asked me, if the current databases should be upraded. I confirmed that.
Unfortunately it hasn't found the databases in that directory, so I have now just acces to the system database.
My question is: Can I recover the databases which are laying in /var/lib/arangodb3/databases somehow?
Do you have a copy of the "var/lib/arangodb3" directory (which includes "databases" as a subfolder) as well? If so, copy the folder to a location on your new machine where Arangodb 3.4.2.1 is installed. You also have to make sure to give the user arangodb access to this folder with the following command:
chown -R arangodb:arangodb /path/to/your/arangodb3RecoveryFolder
Next you can modify the arangod.conf (located at /etc/arangodb3/arangod.conf) to point to your recovery arangodb3 folder.
[database]
directory = /path/to/your/arangodb3RecoveryFolder
Then stop the arangodb3 service with sudo service arangodb3 stop,
run sudo service arangodb3 upgrade to upgrade the database directory and sudo service arangodb3 start to start the service again.
You can check if the service is running by executing sudo service arangodb3 status. In case it is not working, have a look at potential error messages in the log file (/var/log/arangodb3/arangod.log).
I am trying to setup environment variables so that any user on a particular server can run commands like nodetool or cqlsh from any where in linux file system . The effort to traverse to bin directory everytime should be saved .
How can we achieve this ? My DSE 4.8 is a tarball install .
Nodetool is usually available to any user that has execution privileges in your linux boxes
For cqlsh, you can set any configuration inside the cqlshrc file (usually found in $HOME/.cassandra/cqlshrc; we have used to enable client-node encryption but has more configurable options
To setup environment variable just follow some steps from root user:
# vi /etc/profile.d/cassandra.sh
Add the following lines to the cassandra.sh file-
export CASSANDRA_HOME=/opt/apache-cassandra-3.0.8
export CASSANDRA_CONF_DIR=/opt/apache-cassandra-3.0.8/conf
Here /opt/ is my directory, where I've extracted my apache-cassandra-3.0.8-bin.tar.gz tarball.
After adding those lines to cassandra.sh, save and exit. Then-
# source /etc/profile.d/cassandra.sh
I've followed these instructions to install Cassandra: http://docs.datastax.com/en/cassandra/2.0/cassandra/install/installDeb_t.html
When I do $ cqlsh terminal replies me with
Connection error: Could not connect to localhost:9160
I read that the issue might be with configuration file cassandra.yaml
However, I turned out I can't access it. My etc/cassandra folder is empty: enter image description here
How to access cassandra.yaml?
Where is cassandra is stored in my project?
Is there a way to check if Cassandra is actually set up in project?
The image you have attached is showing the ~/.cassandra directory off of your home dir. That's not the same as/etc/cassandra. You should be able to confirm this with the following command:
$ ls -al /etc/cassandra/cassandra.yaml
-rw-r--r-- 1 cassandra cassandra 43985 Mar 11 12:46 /etc/cassandra/cassandra.yaml
To verify if Cassandra is even running, this should work for you if you have successfully completed the packaged install:
$ sudo service cassandra status
Otherwise, simply running this should work, too:
$ ps -ef | grep cassandra
When you set up Cassandra, you'll want to set the listen_address and rpc_address to the machine's hostname or IP. They're set to localhost by default, so if it's running cqlsh should connect to that automatically.
My guess is that Cassandra is not starting for you. Check the system.log file, which (for the packaged install) is stored in /var/logs/cassandra:
$ cat /var/log/cassandra/system.log
Check out that file, and you might find some clues as to what is happening here.
Also, did you really install Cassandra 2.0? That version has been deprecated, so for a new install you shouldn't go any lower than Cassandra 2.1.
I want to connect to cassandra but got this error:
$ bin/cqlsh
Connection error: ('Unable to connect to any servers', {'192.168.1.200': error(10061, "Tried connecting to [('192.168.1.200', 9042)]. Last error: No connection could be made because the target machine actively refused it")})
Pretty simple.
The machine is actively refusing it because your system does not have cassandra running on it. Follow the following steps to completely get rid of this trouble :
Install Cassandra from DataStax (Datastax-DDC; Cassandra version 3).
Go to ~\installation\path\DataStax-DDC\apache-cassandra\bin.
Open up cmd there. (Use Alt+F+P to open it if you are on windows 8 or later).
type cassandra -f this will generate a lot of stuff on the window and you must get the last line as INFO 11:32:31 Created default superuser role 'cassandra'
Now open another cmd window in the same folder.
Type cqlsh
This should give you a prompt, without any error.
I also discovered that this error doesn't pop up if I use cassadra v2.x found here Archived version of Cassandra. I don't know why :( (If you find out please comment).
So, if the above steps do not work, you can always go back to Cassandra v2.x.
Cheers.
Check if you have started Cassandra server, then provide the host and port as the arguments.
$ bin/cqlsh 127.0.0.1 4092
I run into the same problem. This worked for me.
Go to any directory for example E:\ (doesn't have to be the same disc as the cassandra installation)
Create the following directories
E:\cassandra\storage\commitlogs
E:\cassandra\storage\data
E:\cassandra\storage\savedcaches
Then go to your cassandra installations conf path. In my case.
D:\DataStax-DDC\apache-cassandra\conf
Open cassandra.yaml. Edit the lines containing: data_file_directories, commitlog_directory, saved_caches_directory to look like the code below (change paths accordingly to where you created the folders)
data_file_directories:
- E:\cassandra\storage\data
commitlog_directory: E:\cassandra\storage\commitlog
saved_caches_directory: E:\cassandra\storage\savedcaches
Then open the cmd (I did it as administrator, but didn't check if it is necessary) to your cassandra installations bin path. In my case.
D:\DataStax-DDC\apache-cassandra\bin
run cassandra -f
Lots of stuff will be logged to your screen.
You should now be able to run cqlsh and all other stuff without problems.
Edit: The operating system was windows10 64bit
Edit2: If it stops working after a while check if the service is till running using nodetool status. If it isn't follow this instruction.
I also faced the same problem on a Win32 windows 7 machine.
Check if you have JAVA installed correctly and JAVA_HOME variable set.
Once you have checked the java installation and set JAVA_HOME, uninstall Cassandra and install it again.
Hopefully this would solve the problem. Mine was solved after applying the above two steps.
You need to mention host, user, password for cassandra cqlsh connection. Default cassandra cqlsh user is cassandra and password is cassandra.
$ bin/cqlsh <host> -u cassandra -p cassandra
I also had same problem. I applied many methods given on google and youtube but none of them worked in my case. Finally, I applied the following 3 steps and it worked in my case:-
Create a folder without any space in C or D whichever is your system drive. eg:- C:\cassandra
Install Cassandra in this folder instead of installing in"Program Files".
After installation, it will be like this- C:\cassandra\apache-cassandra-3.11.6
Copy python 2.7 installed in bin folder i.e.,C:\cassandra\apache-cassandra-3.11.6\bin
Now your program is ready for work.
There is no special method to connect cqlsh it simple as below:-
$ bin/cqlsh 127.0.0.1(host IP) 9042 or $ bin/cqlsh 127.0.0.1(host IP) 9160 (if older version of Cassandra)
Don't forget to check port connectivity if you are connecting cqlsh to remote host. Also you can use username/password if you enabled by default it is disabled.
I am using Cassandra 1.2 db on windows 7.
I want to take the back up of a keyspace.
I am doing as following:
C:\Workspace\apache-cassandra-1.2.4-bin\bin> nodetool -h localhost -p 7199 snaps
hot myDb
Starting NodeTool
Requested snapshot for: myDb
Snapshot directory: 1371534210892
C:\Workspace\apache-cassandra-1.2.4-bin\bin>
So it shows snapshot directory as 1371534210892 . What does it mean?
Where can I find the snapshot just created ?
TL;DR;
Check C:\var\lib\cassandra\data\system\myDb\snapshots\1371534210892
Before I provide details its important that you know my environment so you can compare.
How I setup Cassandra
I downloaded the zip from Apache's website then I unzipped it to C:\apache-cassandra-1.2.5 and finally I added the CASSANDRA_HOME environment variable.
How I start / backup Cassandra
I start cassandra by running startup.bat in the bin folder:
C:\apache-cassandra-1.2.4\bin\cassandra.bat
I backup cassandra by running the same command that you did (I backed up system because it was a fresh cassandra install):
nodetool -h localhost snapshot system
# output:
Starting NodeTool
Requested snapshot for: system
Snapshot directory: 1371547087563
I then browsed to the following directory where I found the 1371547087563 folder:
C:\var\lib\cassandra\data\system\local\snapshots
The snapshot is also created for every other keyspace so with a clean install I could find it in:
C:\var\lib\cassandra\data\system\schema_columns\snapshots
C:\var\lib\cassandra\data\system\schema_columnfamilies\snapshots
C:\var\lib\cassandra\data\system\schema_keyspaces
So basically it backups up the 4 internal keyspaces (system, schema_columns, schema_columnfamilies, schema_keyspaces) and the keyspace that you provide on the end as a parameter to the nodetool command, but because I specified system as the param, the command created snapshots of the 4 internal keyspaces only.
In your case the fifth keyspace would be the one you are after.
find 1371534210892 folder inside cassandra/data/yourkeyspacename (equivalent to folder/var/lib/data/yourkeyspacename in LINUX) here each CF have 1371534210892 folder under snapshot directory which is latest one,
This base cassandra folder is the one which you generated during installation not the one having bin and all directories