I have an existing database for which i was looking to create a new clustered environment. I tried the following steps:
Create a new database instance (OS & DB Server).
Take a backup / snapshot from existing database server for all the databases.
Import the snapshot to the new server.
Configure the cluster - referred to various sites but all giving same solution. Example reference site - https://vexxhost.com/resources/tutorials/how-to-configure-a-galera-cluster-with-mariadb-on-ubuntu-12-04/
Ran the command (sudo galera_new_cluster) on the primary server. (Primary server - no issue starting up). But when we tried starting the secondary server - it actually crashed for some reason.
Unfortunately at this point, dont have the logs stored / backed up with me where it failed. But it seemed like it tried to sync in with the primary server - had some failure with that.
As for additional part of the actions performed above. Both the server with same username / password - created a passwordless ssh connection between both the machines. Also, the method of syncing is set to rsync.
Am i missing something or doing it wrong? Is there a better way available on it?
Related
We're trying to move ASP.NET session state for one of our Azure web apps into a database, and it seems like the aspnet_regsql.exe tool is the way to go. Unfortunately, I'm getting stuck on a few issues below. It's an Azure SQL database, and I'm connecting using the server's admin account.
I initially wanted to add the session tables to our existing database, so I ran .\aspnet_regsql.exe -U adminusername -P adminpassword -S servername.database.windows.net -d databasename -ssadd -sstype c. Which throws the exception "Database 'databasename' already exists. Choose a different database name"
Omitting the database name and running it again throws the exception: "Execution Timeout Expired" after about 30 seconds, which is just the default for SqlCommand.CommandTimeout. This occurs while executing the "CREATE DATABASE" command. I tried creating a database manually, and it takes about 50 seconds for some reason. This database is S0 tier and is not under any load
Running aspnet_regsql again on the already-created database (because it's idempotent, right?) leads to the "Database already exists" error, as does pre-creating an empty database for it to start from.
There's no flag that lets me increase the timeout, and I can't set command timeout using the -C (connection string) flag
Adding the -sqlexportonly flag to generate a script and just running that directly doesn't work either (yes, I know I'm not supposed to run InstallSqlState.sql directly). It throws a whole load of error messages saying things like:
Reference to database and/or server name in 'msdb.dbo.sp_add_job' is not supported in this version of SQL Server.
USE statement is not supported to switch between databases.
Which makes me think this script might have some issues with an Azure SQL database...
Does anyone have any ideas?
Update:
It looks like all the errors involving 'msdb' are related to removing and re-adding a database job called 'Job_DeleteExpiredSessions'. Azure SQL doesn't support database jobs, so the only options I can see are
Run SQL on a VM instead (vastly more expensive, and I'd rather stick with the platform services than have to manage VMs)
Implement one of those "Elastic Job Agents"
Perhaps move the same functionality elsewhere (e.g. a stored proc)?
Turns out Microsoft has an article about how to do exactly what I need, which I somehow
missed during my searching yesterday. Hopefully this answer saves someone else a few hours of frustration. All the info you need is at https://azure.microsoft.com/en-au/blog/using-sql-azure-for-session-state/ earlier.
Note that YMMV since it's from 2010 and also says in scary red letters
"Microsoft does not support SQL Session State Management using SQL Azure databases for ASP.net applications"
Nevertheless, they provide a working script that seems to do exactly what I need.
I want get for a given database/table the list of groups this database/table has been granted access in sentry.
There does not appear to be a Sentry SHOW command for this purpose in the documentation.
This blog post suggests that you can instead query the Sentry database directly (assuming you are using the Sentry service, not policy files).
However, at present there is no command to show the group to role
mapping. The only way to do this is by connecting to the Sentry
database and deriving this information from the tables in the
database.
If you're using CDH you can determine which node in the cluster is
running the Sentry database using Cloudera Manager, navigating to
Clusters > Sentry, then clicking Sentry Server and then
Configuration. Here you will find the type of database being used
(e.g. MySQL, PostgreSQL, Oracle), the server the databases is running
on, it's port, the database name and user.
You will need the Sentry database password - the blog post gives a suggestion for retrieving it if you do not know it.
An example query for a PostgreSQL database is given:
SELECT "SENTRY_ROLE"."ROLE_NAME","SENTRY_GROUP"."GROUP_NAME"
FROM "SENTRY_ROLE_GROUP_MAP"
JOIN "SENTRY_ROLE" ON "SENTRY_ROLE"."ROLE_ID"="SENTRY_ROLE_GROUP_MAP"."ROLE_ID"
JOIN "SENTRY_GROUP" ON "SENTRY_GROUP"."GROUP_ID"="SENTRY_ROLE_GROUP_MAP"."GROUP_ID";
However, I have not tried this query myself.
This should work for MySQL:
SELECT R.ROLE_NAME, G.GROUP_NAME
FROM SENTRY_ROLE_GROUP_MAP RGM
JOIN SENTRY_ROLE R ON R.ROLE_ID=RGM.ROLE_ID
JOIN SENTRY_GROUP G ON G.GROUP_ID=RGM.GROUP_ID;
I'm trying to create shiny app in shiny.io which requires access to a MySQL database which is located in my local machine. Is it possible to use RMySQL to connect to the local database by shiny.io? And how can I do that?
I'm a little "late" with my answer, but keep in mind that if you are deploying to shiny.io then "localhost" is pointing to shiny.io and there is no mysql for you there :-) So you should have to open your MySQL server and use your public IP address in "host" variable. Not that I am proposing this, from the security point of view it is not wise to open your MySQL server to the public. If you follow this way, at least, you should filter connections to only allow the IP address of shiny.io.
Another solution -more reasonable, in my opinion- might be to use an already public server that offers you a persistence layer, such as mongohq.com (now compose.io). They use MongoDB (not MySQL) but it could satisfy your needs (and you will get a 512MB RAM testing server for free). You may want to study this working example that uses shiny.io and mongo in order to start your project up.
The usage is essentially the same as in regular R script.
you can put this at the top of your server.R file
library(RMySQL)
con = dbConnect(MySQL(), user='myusername', password='mysillypassword', db='dataaa', host='localhost')
query = "SELECT 1"
result = dbGetQuery(con, query)
Now result will be available for the rest of the shiny app.
You can also build the query inside a reactive function, and dynamically query the database.
Within your mySQL database, whitelist shinyapps.io IP addresses.
See this helpful post from Rstudio support.
As per this how-to, I've successfully configured IIS on my XP-SP3 dev box for SQL Server 2008 Express to save ASP.NET session state information. I'm just using SQL Server because otherwise on every recompile, I was losing the session state which was obnoxious (having to re-login). But, I'm facing an annoying issue in that every time I restart SQL there's this error, and sometimes one or two other very similar friends:
The SELECT permission was denied on the object 'ASPStateTempSessions',
database 'tempdb', schema 'dbo'.
To fix the error, I just open Management Studio and edit the User Mapping for the login/dbo I'm using on the ASPState db, and re-add tempdb to that user with all but deny permissions. Apparently, once the right permissions are there, ASP.NET is able to automatically create the tables it uses. It just can't run that CreateTempTables sproc until the right security is there.
THE QUESTION...
Is there a way to not have to re-do this on every restart of the SQL Server?
I don't really care right now about keeping the temp data across restarts, but I would like to not have to go through this manual step just to get my web app working on localhost, which uses session state variables throughout. I suppose one could resort to some kind of stored procedure within SQL Server to accomplish the task for this machine when the service starts, to not have to do it manually. I'd accept such an answer as a quick fix. But, I'm also assuming there's a better recommended configuration or something. Not seeing an answer to this on the how-to guide or elsewhere here on StackOverflow.
Both answers seem valid; but with most things Microsoft, its all in the setup...
First uninstall the ASPState database by using the command:
aspnet_regsql –ssremove –E -S .
Note:
-E is to indicate you want to use integrated security connection.
-S informs what SQL server and SQL instance to use, and the "." (dot) specifies default local instance
Then re-install using the command:
aspnet_regsql –ssadd –sstype p –E -S .
Note:
The sstype has three options, t | p | c ... the first "t", tells the installer to host all stored procedures in the ASPState database, and all data in the tempdb. The second option "p" tells the installer to persist data to the ASPState database. The last option "c" allows you to specify a different 'custom' database to persist the session state data.
If you reinstall using the "-sstype p" you then need only to supply datareader/datawriter to the ASPState database for the user that's making the connection (in most cases, the application pool's identity in IIS).
The added benefit of persisting the data is that session state is retained even after a restart of the service. The only drawback is that you need to ensure the agent cleanup job is pruning old sessions regularly (it does this by default, every minute).
Important:
If you are running a cluster, you must persist session data. You're only option is to use sstype 'p' or 'c'.
Hope this sheds light on the issue!
For the record, I did find a way to do this.
The issue is that the tempdb is recreated from the model db each time the service restarts. The gist of the solution is to create a stored procedure that does the job, and then make that procedure run at startup.
Source code (credit to the link above) is as follows:
use master
go
-- remove an old version
drop proc AddAppTempDBOwner
go
-- the sp
create proc AddAppTempDBOwner as
declare #sql varchar(200)
select #sql = 'use tempdb' + char(13) + 'exec sp_addrolemember ''db_owner'', ''app'''
exec (#sql)
go
-- add it to the startup
exec sp_procoption 'AddAppTempDBOwner', 'startup', 'true'
go
Well done for finding the strangest way possible to do this.
The correct answer is as follows:
use master
go
EXEC sp_configure 'Cross DB Ownership Chaining', '1'
go
RECONFIGURE
go
EXEC sp_dboption 'ASPState', 'db chaining', 'true'
go
I have a Sql Server 2008 Express database file that's currently being used by an ASP.NET application, and I'm not sure how to query the database without taking the website down.
I'm unable to copy the database files (.mdf and .ldf files) to another directory, since they're in use by the web server. Also, if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt), then the application pool user becomes unable to access the database (i.e. the webpages start producing http 500 errors. I think this might have to do with the username for the application pool becoming somehow divorced from the login credentials in the sql server database).
Any suggestions? I realize this is probably a newbie question, since it seems like a rather fundamental task. However, due to my inexperience, I really don't know what the answer is, and I'm pretty stumped at this point, since I've tried a couple of different things.
Thanks!
Andrew
if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt),
Don't do this to a live database - it's attempting to be setup an MDF to be written to by two different databases...
Use Backup/Restore
As you've found, Attach/ReAttach requires the database to be offline - use the Backup/Restore functionality:
MSDN: Using SSMS to Backup the Database
MSDN: Using SSMs to Restore the Backup
Be aware that the backup/restore doesn't maintain logins (& jobs if you have any associated with the database) - you'll have to recreate & sync if using an account other than those with uber access.
Maybe Linked Server would work?
Another alternative would be to setup another SQL Server Express/etc instance on a different box, and use the Linked Server functionality to create a connection to the live/prod data. Use a different account than the one used for the ASP application...