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Description
K8S uses ConfigMap to store configuration files, for example:
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
name: srs-config
data:
srs.conf: |-
listen 1935;
max_connections 1000;
daemon off;
http_api {
enabled on;
listen 1985;
}
http_server {
enabled on;
listen 8080;
}
vhost __defaultVhost__ {
http_remux {
enabled on;
}
hls {
enabled on;
}
}
EOFConfigMap will be mounted as a volume and become a configuration file:
cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
name: srs-deploy
labels:
app: srs
spec:
replicas: 1
selector:
matchLabels:
app: srs
template:
metadata:
labels:
app: srs
spec:
volumes:
- name: config-volume
configMap:
name: srs-config
containers:
- name: srs
image: ossrs/srs:3
imagePullPolicy: IfNotPresent
ports:
- containerPort: 1935
- containerPort: 1985
- containerPort: 8080
volumeMounts:
- name: config-volume
mountPath: /usr/local/srs/conf
EOFYou can view the running pods:
Mac:trunk chengli.ycl$ pod=`kubectl get po|grep srs-deploy|awk '{print $1}'`
Mac:trunk chengli.ycl$ kubectl exec $pod -- cat conf/srs.conf && echo ""
listen 1935;
max_connections 1000;
daemon off;
http_api {
enabled on;
listen 1985;
}
http_server {
enabled on;
listen 8080;
}
vhost __defaultVhost__ {
http_remux {
enabled on;
}
hls {
enabled on;
}
}When ConfigMap changes, you can use fsnotify to receive notifications of file changes, thereby triggering the reload of SRS.
TRANS_BY_GPT3
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winlinvip commentedon Mar 12, 2020
The paragraph in Aliyun's SLS log service says link is as follows:
Another solution is to listen for changes in the configuration file. However, there is an issue where the fsnotify signal may not be received due to symbolic links: link
Here is an example of Nginx's reload, which is implemented using fsnotify: link
You can see that it also listens for changes in the file directory and then sends the SIGHUP (reload) signal to Nginx.
TRANS_BY_GPT3winlinvip commentedon Mar 12, 2020
It is implemented using inotify under Linux.
Since inotify returns an fd and can be initialized as non-blocking mode using inotify_init1, reading it using read is an IO operation, so we should be able to use ST to read this fd.
TRANS_BY_GPT3winlinvip commentedon Mar 12, 2020
SRS has added two configurations, automatically enabling auto reload under Docker, and disabling auto reload outside of Docker.
The added log prints are as follows:
You can see that there is an additional fd=10, a_inode(inotify):
TRANS_BY_GPT3For #1635, inotify watch ConfigMap for reload. 3.0.130
winlinvip commentedon Mar 12, 2020
If the file is deleted or moved, and then created again (as part of the ConfigMap update logic).
When a file is deleted, including the target of symbolic links being moved or deleted:
When a file is created, including the creation of the target of symbolic links:
TRANS_BY_GPT3For #1635, inotify watch ConfigMap for reload. 3.0.131
winlinvip commentedon Mar 12, 2020
K8S will have a ..data subdirectory:
All events of K8S are as follows:
The key events are as follows, it appears that K8S executed a command similar to
ln -sf ..2020_03_12_14_17_54.925365984 ..data_tmp && mv ..data_tmp ..data:inotifyshould listen to theconfdirectory.confdirectory,IN_MODIFY | IN_CREATE | IN_MOVED_TO, so that the creation of the..datasubdirectory can also be detected.After receiving the event, it is necessary to determine the file name. Only if it is
srs.confor..data, it is considered a reload, and others are ignored.TRANS_BY_GPT3For #1635, inotify watch ConfigMap for reload. 3.0.132
For #1635, inotify watch ConfigMap for reload. 3.0.133
For #1635, inotify watch ConfigMap for reload. 3.0.134
For #1635, refine inotify watch for relative path
For #1635, refine inotify watch for relative path