HAA - "Cannot allocate nodes for shards" when creating Redis DB

[codemonkee (Tim)]

Hi @Vikas_Kadam - I am wondering if you overcame this challenge? I am facing something similar but it is on the master node during the DB Creation.

post_create_db(){
    cat<<EOF
{
    "name": "uipath-orchestrator",
    "type": "redis",
    "memory_size": 2147483648,
    "port" : 10000,
    "slave_ha": true,
    "authentication_redis_pass": "${PASSWORD}",
    "uid": 3
}
EOF
}

curl -u "${USERNAME}:${PASSWORD}" -k -i -H "Accept: application/json" -H "Content-Type:application/json" -X POST --data "$(post_create_db)" "https://127.0.0.1:9443/v1/bdbs"

The outcome of which is

HTTP/1.1 406 NOT ACCEPTABLE
Server: nginx
Date: Tue, 27 Apr 2021 07:29:03 GMT
Content-Type: application/json
Content-Length: 150
Connection: keep-alive

{"description":"Cannot allocate nodes for shards","error_code":"insufficient_resources","error_details":{"error":"cannot_allocate_nodes_for_shards"}}

• OS Firewall (Firewalld) is disabled
• 8 CPU, 16GB RAM, +240GB Disk
• Redis appears to install okay (Cluster is created and Node is registered)
• Attempting to create DB via Web UI errors with “Cluster memory is fully allocated”

I’ve opened a ticket with UiPath Support and waiting a response as well I have been combing the Redis Enterprise Software documentation without much luck on the specific error or the API asides from the general steps on how to create a database through the Web UI.

[codemonkee (Tim)]

After some sleuthing while waiting for Support, I determine the culprit to be IPTables. This didn’t immediately come to mind as there were some odd symptoms

• Redis installed without error
• Cluster was created successfully by API
• Node Registered successfully by API
• DB would not create by API nor by Web UI
• rladmin status was slow to respond, and python script would crap out when attempting to get the status on the shards. In addition FREE RAM and PROVISIONAL RAM was reading at 0KB/16GB

Through some troubleshooting I Started Firewalld and added the required ports documented by both UiPath and Redis Enterprise. I was able to create the database and rladmin status was responsive.

I then rebooted the host and the the original symptoms came back. After digging through the service logs, I noticed that IPTables had been starting up, but stopping when I started Firewalld.

Disabling / Stopping Firewalld and IPTables allowed the DB to be created.

Disable the local firewall is not recommended, we happen to have other security measures in place for our VMs

Didn’t solve the issue but a reference that got me thinking a little bit more.
https://docs.redislabs.com/latest/rs/installing-upgrading/configuring/centos-rhel-7-firewall/