We have a redis cache hosted on Azure and we use the following as a service in our .net core application:
services.AddSingleton<IConnectionMultiplexer>(provider =>
ConnectionMultiplexer.Connect(Configuration.GetConnectionString("RedisConnection"))
);
Our connection string is similar to the following:
ourserver.redis.cache.windows.net:6380,password=******=,ssl=True,abortConnect=False,syncTimeout=4000
in getting from cache we don't face problems but if we add to cache we sometimes get the following error:
"StackExchange.Redis.RedisConnectionException: It was not possible to
connect to the redis server(s); to create a disconnected multiplexer,
disable AbortOnConnectFail. ConnectTimeout"
I have read solutions like setting abortconnect to false and increasing the timeout but I have implemented it like the connection string above.
If you have suggestions or you think that we have a problem with the connection string kindly advise.
Update: we have implemented a solution to solve connectivity issue but now we get this:
StackExchange.Redis.RedisConnectionException: No connection is available to service this operation
What is your connectTimeout set to? Can you try increasing that to see if it helps?
Related
I have a basic Pulsar app, and when I try to connect to Pulsar, I get this exception:
2021-03-10 14:38:26.107 WARN 7 --- [r-client-io-1-1]
o.a.pulsar.client.impl.ConnectionPool : Failed to open connection
to my-pulsar-server-ms-tls.domain.com:6651 :
io.netty.channel.ConnectTimeoutException: connection timed out:
my-pulsar-server-ms-tls.domain.com/10.80.13.38:6651 2021-03-10
14:38:26.212 WARN 7 --- [al-listener-3-1]
o.a.pulsar.client.impl.PulsarClientImpl : [topic:
persistent://myTenant/myNamespace/myTopic]
Could not get connection while getPartitionedTopicMetadata -- Will try
again in 100 ms
My Pulsar client is pretty basic:
PulsarClient.builder()
.serviceUrl(serviceUrl)
.authentication(AuthenticationFactory.token(authToken))
.tlsTrustCertsFilePath(serverCertificateFilePath.toString())
.enableTlsHostnameVerification(false)
.allowTlsInsecureConnection(false)
.build();
The producer is also pretty basic and looks like this:
pulsarClient.newProducer(Schema.STRING)
.topic(topic)
.create();
I've verified that the token and TLS cert are correct. I've also tried connecting a consumer from this same environment and got a similar exception, and I know that others with the same code are able to connect to the same Pulsar cluster from other environments. What is the issue?
Your connection is getting blocked by a firewall or network issue.
Verify that you can establish a connection to your endpoint my-pulsar-server-ms-tls.domain.com:6651 from your environment.
If you're able to run a network packet dump (like tcpdump), that should make it obvious if you're not able to establish a connection.
You can also try running curl my-pulsar-server-ms-tls.domain.com:6651, and if you get back some html, that means you were able to reach the server. However, if you get Could not resolve host, then you were blocked by the network configuration (such as a missing route) or firewall.
I have a Blazor server side app published on IIS 10.
When browsing to an arbitrary page and just letting it idle after a minute or so (sometimes only 45 sec, sometimes something between 1 and two minutes) the modal
Attempting to reconnect to server ...
appears for a couple of seconds.
In the browser console the logging shows either
Error: Connection disconnected with error 'Error: Server timeout
elapsed without receiving a message from the server.'.
or
Information: Connection disconnected.
Since this seems to be a timeout problem I added the following options to ConfigureServices in my startup.cs
services.AddServerSideBlazor()
.AddHubOptions(options =>
{
options.ClientTimeoutInterval = TimeSpan.FromMinutes(10);
options.KeepAliveInterval = TimeSpan.FromSeconds(3);
options.HandshakeTimeout = TimeSpan.FromMinutes(10);
});
This does not solve the problem though.
I also went to the advanced settings of my site in IIS and increased the connection timeout from the default 120 sec to 600 sec. This did not help either.
Those frequent disconnections only happen on the live site hosted on IIS 10.
If I start the app locally with Visual Studio the connection is stable.
Any hints of what I'm missing would be appreciated!
Update:
As suggested by #agua from mars in comment below I changed transport type like this
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.MapBlazorHub(options => { options.Transports = HttpTransportType.LongPolling; });
endpoints.MapFallbackToPage("/_Host");
});
With this change the connection is still closed. The console log shows
Information: (LongPolling transport) Poll terminated by server.
I also tried HttpTransportType.ServerSentEvents which does not work at all but gives this error
Error: Failed to start the connection: Error: Unable to connect to the
server with any of the available transports. ServerSentEvents failed:
Error: 'ServerSentEvents' does not support Binary.
Update 2:
The IIS is configured to use HTTP 1.1
I tried changing to HTTP/2 but this did not change anything regarding the disconnections.
This is related to application pool recycling in IIS as stated by #Programmer. You can reproduce this by going into the application pool, right click the pool and choose recycle to force it. Your blazor app will get the "reconnect modal screen".
For me, I did not want to disable pool recycle, so I added js in the _Hosts.cshtml file as
<script>Blazor.defaultReconnectionHandler._reconnectCallback = function (d) {document.location.reload();}</script>
to automatically reconnect when the server comes back up.
Try this out..
app.UseEndpoints(endpoints =>
{
//other settings
.
.
endpoints.MapBlazorHub(options => options.WebSockets.CloseTimeout = new TimeSpan(1, 1, 1));
//other settings
.
.
});
This could be related to IIS application pool recycling. Try disabling the recycling to see if that's casing the disconnection.
I suffer the same problem on my Blazor server too: Myspector.com
I am sure this comes from network of data provider. I use Othello in Germany with 4G and see disconnection in 5 sec . When I am with wifi with t online on same target server no disconnection at all.
I Think some operators are incompatible with Blazor server/websoscket....
My recent experience especially on a shared server, increase the pool memory. Connectivity issues went away when we bumped 256MB up to 1GB for a small user base.
I'm testing Azure SQL Serverless and from SSMS it seems to work fine, but from my ASP.NET Core application it never wakes up.
Using SSMS I can open a connection to a sleeping Serverless SQL database and after a delay the connection will go through.
Using my ASP.NET Core application I tried the same. From the login page I tried to login, which opens a connection to the database. After 10 or 11 seconds (I looked up the default timeout and its supposed to be 15 seconds but in this case it always seems to be about 10.5 seconds +/-0.5s). According to the docs, the first connection attempt may fail but subsequent ones should succeed, but I can send multiple queries to the database and it always fails with the following error:
Microsoft.Data.SqlClient.SqlException (0x80131904): Database 'myDb' on server
'MyDbSvr.database.windows.net' is not currently available. Please retry the connection later. If the
problem persists, contact customer support, and provide them the session tracing ID of
'{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}'.
If I wake the database up using SSMS then the login web page can connect to the database and succeeds.
I have added Connect Timeout=120; to the connection string.
The connection does happen during an HTTP request that is marked async on the Controller, thought I don't know if that makes any difference.
Am I doing something wrong or is there something additional I need to do to get the DB to wake?
[updte]
as an extra test wrote the following test
void Main()
{
SqlConnection con = new SqlConnection("Server=mydbsvr.database.windows.net;Database=mydb;User Id=abc;Password=xyz;Connect Timeout=120;");
Console.WriteLine(con.ConnectionTimeout);
con.Open();
var cmd = con.CreateCommand();
cmd.CommandText = "select getdate();";
Console.WriteLine(cmd.ExecuteScalar());
}
and got the same error.
I figured it out and its the dumbest thing.
This Azure SQL Server instance was migrated from another subscription and the group that migrated it gave it a new name, but they did something that allowed the use of the old name also. I'm researching to figure out how that was done. I will update this answer when I find out what that was.
As it turns out, using the old name with an Serverless Database won't wake up the db. Don't know why. But if you change to use the new/real server name it works. you do have to add a retry to the connection as it may fail the first few times.
[Update]
The new server allows logins using the old name by using a Azure SQL Database Alias https://learn.microsoft.com/en-us/azure/sql-database/dns-alias-overview
I followed the official instructions of Azure Portal. This is my
config.properties:
cassandra_host="demodemodemo.cassandra.cosmosdb.azure.com"
cassandra_username="demo"
cassandra_password="aHaplLoWhRlysBrtJWiOwB79TkqSU9PjKLu5wDeltLqys5NpR9vmtHCJrTF4ScdY69yNSWUvTUphax8RijydTA=="
cassandra_port=10350
ssl_keystore_file_path=
ssl_keystore_password=
Then it throws java.lang.IllegalArgumentException: Failed to add contact point and Caused by: java.net.UnknownHostException: "demodemodemo.cassandra.cosmosdb.azure.com" at this point:
[ CassandraUtils class, getSession() method ]
cluster = Cluster.builder()
.addContactPoint(cassandraHost)
You need to remove the double quotes from the settings.
If your credentials are correct, this should work.
cassandra_host=demodemodemo.cassandra.cosmosdb.azure.com
cassandra_username=demo
cassandra_password=aHaplLoWhRlysBrtJWiOwB79TkqSU9PjKLu5wDeltLqys5NpR9vmtHCJrTF4ScdY69yNSWUvTUphax8RijydTA==
cassandra_port=10350
Also by default the username is the same as the first part of the host so in your case demodemodemo except if you changed it.
I had similar problem. My corporate on prem environment is behind a proxy. Since I was using cassandra, I could not setup a http-proxy (it has its own protocol). The solution might be to use Azure Private Link. An example tutorial on how to do it is here: https://learn.microsoft.com/en-us/azure/cosmos-db/how-to-configure-private-endpoints
I'm referring this tutorial to create a device identity. However, getting an exception as below:
Here is my config file:
Edit:
What is this Instrumentation key and value in App.Config? I just copied from the sample code. However, from where can I get it, in case I'm using a real device?
Am I missing any SDK or anything else?
Do I need to download something extra? the tutorial does not suggest anything.
Even when I'm running sample code from GiTHub getting the same error.
the following screen snippet shows a reason of this error, such as connectionString.
Use the connectionString from your Azure IoT Hub - see the tutorial section Create an IoT Hub step 6.
Can you check that the connection string you're using is in the correct format. It should look like:
"HostName={your hub name}.azure-devices.net;SharedAccessKeyName=iothubowner;SharedAccessKey={your key}"
You can copy the complete connection string from the portal as described in the tutorial.
Issue resolve: I was missing my connection string.Which I got from "IoTHubOwner" from Azure portal login. :)