Set up high availability for Digital Access component
This article is valid for Digital Access 6.1.0 and later and Smart ID 21.10 and later.
Smart ID Digital Access component supports distributed mode to enable high availability and failover that provides powerful flexibility and scalability. With this mode, Digital Access component will switch to a redundant service once the primary one has stopped working. Thereby, not only one but several redundant services are supported. Using high availability enables systems to meet high service-level agreement (SLA) requirements.
This article describes the setup of high availability for two Digital Access components with docker swarm and running services. See also High availability architecture for Digital Access component.
Manager node is the node that hosts the administration service.
Worker node is a node that hosts other services, not running the administration service.
Prerequisites
The following prerequisites apply:
The following ports shall be open to traffic to and from each Docker host participating on an overlay network:
TCP port 2377 for cluster management communications
TCP and UDP port 7946 for communication among nodes
UDP port 4789 for overlay network traffic
For more details refer to: https://docs.docker.com/network/overlay/
Keep a note of IP addresses of nodes where access point is running.
Step-by-step instruction
Get cluster join token and stop services - manager node
SSH to the node running administration service, that is, the manager node.
Get the cluster join token by running this command. This token will be used for joining worker nodes to the manager node.
Get token
CODEsudo docker swarm join-token worker
Output of the command will be like:
docker swarm join --token SWMTKN-1-5dxny21y4oslz87lqjzz4wj2wejy6vicjtqwq33mvqqni42ki2-1gvl9xiqcrlxuxoafesxampwq 192.168.253.139:2377
Stop services
Stop the running services.
Stop services
CODEsudo docker stack rm <your da stack name>
Join as worker nodes
Do these steps on all worker nodes:
SSH to the worker node(s).
Stop the running services.
CODEsudo docker stack rm <your da stack name>
Get the node ID.
CODEsudo docker node ls
Remove the labels for running services.
CODEsudo docker node update --label-rm da-access-point <nodeid> sudo docker node update --label-rm da-authentication-service <nodeid> sudo docker node update --label-rm da-distribution-service <nodeid> sudo docker node update --label-rm da-policy-service <nodeid>
if you are using PostgreSQL as database then remove label using this command (not to run on PostgreSQL node):
CODEsudo docker node update --label-rm postgres <nodeid>
Remove the node from the current swarm.
CODEsudo docker swarm leave --force
Join to manager swarm using the command output from "Get cluster join token" above.
CODEdocker swarm join --token SWMTKN-1-5dxny21y4oslz87lqjzz4wj2wejy6vicjtqwq33mvqqni42ki2-1gvl9xiqcrlxuxoafesxampwq 192.168.253.139:2377
On success, the output will be: This node joined a swarm as a worker.
Remove labels at manager node
SSH to manager node.
Remove label for all services which are not required on this node.
Remove label
CODEsudo docker node update --label-rm da-access-point <nodeid>
Edit configuration files - Manager node
policy:
# configure image tag from versiontag.yaml
hostname: policy
deploy:
mode: replicated
replicas: 1
placement:
constraints:
#If you need to set constraints using node name
#- node.hostname ==<node name>
# use node label
[node.labels.da-policy-service == true ]
resources:
limits:
cpus: "0.50"
memory: 512M
reservations:
cpus: "0.10"
memory: 128M
volumes:
- /opt/nexus/config/policy-service:/etc/nexus/policy-service:z
- /etc/localtime:/etc/localtime
- /etc/timezone:/etc/timezone
logging:
options:
max-size: 10m
policy1:
# configure image tag from versiontag.yaml
hostname: policy1
deploy:
mode: replicated
replicas: 1
placement:
constraints:
#If you need to set constraints using node name
#- node.hostname ==<node name>
# use node label
[node.labels.da-policy-service1 == true ]
resources:
limits:
cpus: "0.50"
memory: 512M
reservations:
cpus: "0.10"
memory: 128M
volumes:
- /opt/nexus/config/policy-service:/etc/nexus/policy-service:z
- /etc/localtime:/etc/localtime
- /etc/timezone:/etc/timezone
logging:
options:
max-size: 10m
network.yml
For each service add network configuration in the network.yml file. For example, if you want to deploy two policy services on two nodes you will have two blocks of configuration as shown below.
Example:
Change the value of:
Service name: Service name should be identical to what is mentioned in docker-compose.yml
policy:
ports:
- target: 4443
published: 4443
mode: host
networks:
- da-overlay
policy1:
ports:
- target: 4443
published: 4443
Also make sure all the listeners that are used for access point Load balance are exposed on network.yml.
versiontag.yml
Add one line for each service in this file also.
For example, if you have two policy services with name policy1 and policy2, you will have two lines for each service.
Example:
policy:
image: http://nexusimages.azurecr.io/smartid-digitalaccess/policy-service:6.0.5.60259
policy1:
image: http://nexusimages.azurecr.io/smartid-digitalaccess/policy-service:6.0.5.60259
At manager node
Verify and identify nodes
Verify if all nodes are part of cluster by running this command.
Verify if all nodes are part of cluster
CODEsudo docker node ls
Identify nodes ID, master and worker where the service will be distributed.
Identify nodes
CODEsudo docker node inspect --format '{{ .Status }}' h9u7iiifi6sr85zyszu8xo54l
Output from this command:
{ready 192.168.86.129}
IP address will help to identify the Digital Access node
Add new labels for each service
Add new labels for each service which you want to run in worker nodes. In this example, we have used “1” as postfix for each service name. You can choose any name based on your requirement, but make sure they are in accordance with what we have defined in constraints section in the docker-compose.yml file.
Use these commands to add label for each service:
Commands to add labels
CODEsudo docker node update --label-add da-policy-service1=true <worker node ID> sudo docker node update --label-add da-access-point1=true <worker node ID>
Deploy your stack using this command. To run the command your working directory should be docker-compose.
Deploy DA stack
CODEsudo docker stack deploy --compose-file docker-compose.yml -c network.yml -c versiontag.yml <your da stack name>
Here:
docker stack deploy
is the command to deploy services as stack.compose file flag is used to provide the file name of base docker-compose file.
-c
is short for–compose-file
flag. It is used to provide override files for docker -compose.<your da stack name>
is the name of the stack. You can change it based on requirements.
Updates in Digital Access Admin
Log in to Digital Access Admin and change the internal host and port for each added service according to the docker-compose.yml and network.yml files.
Go to Manage System > Distribution Services and
Check Listen on all interfaces in case of the ports that are to be exposed
Also check Distribute key files automatically.
Go to Manage System >Access Points and provide the IP address instead of the service name. Also enable the "Listen on all Interfaces" option.
Final steps
Make sure all services are stopped, else remove stack using this command in the manager node:
Remove stack
CODEsudo docker stack rm <da/stack Name>
In worker node, edit service Local Configuration file, and provide values for:
<core> <id>6</id> </core>
<attribute name="mHost" type="string" value="policy1"/>
<attribute name="mId" type="integer" value="6"/>
Copy the keys from manager node to worker node services.
For access point: copy only shared key.
For all services enabled in worker node: copy internal and shared keys.
Example: Copy keys
In manager node -> copy the keys to the home directory of the worker node.
/opt/nexus/config/administration-service/keys# scp internal.key agadmin@<worker node Ip>:/home/agadmin
opt/nexus/config/administration-service/keys# scp shared.key agadmin@@<worker node Ip>:/home/agadmin
In worker node ->
/home/agadmin# cp internal.key opt/nexus/config/policy-service/keys/
/home/agadmin# cp shared.key opt/nexus/config/policy-service/keys/
Deploy your stack using this command. To run the command your working directory should be docker-compose.
Deploy DA stack
CODEsudo docker stack deploy --compose-file docker-compose.yml -c network.yml -c versiontag.yml <your da stack name>
For Database connection issue, restart postgres container
Database connection issue
CODEdocker stop <postgres container ID>
Check connection in Digital Access Admin for IP and password provided.