kubernetes timescaledb statefulset: pod重新创建时丢失的更改
kubernetes timescaledb statefulset: pod重新创建时丢失的更改
提问于 2019-07-22 14:21:04
我有一个时间升级的服务器作为StatefulSet在AKS运行。当我删除并重新创建timescaledb pod时，即使该pod与初始关联的PV (持久卷)相关联，更改也会丢失。任何帮助都是非常感谢的。
下面是通过运行kubectl get statefulset timescaledb -o yaml提取的statefulset的PV、PVC配置
template:
metadata:
creationTimestamp: null
labels:
app: timescaledb
spec:
containers:
- args:
- -c
- config_file=/etc/postgresql/postgresql.conf
env:
- name: POSTGRES_PASSWORD
valueFrom:
secretKeyRef:
key: password
name: timescaledb-secret
image: docker.io/timescale/timescaledb:latest-pg9.6
name: timescaledb-backend
ports:
- containerPort: 5432
name: server
protocol: TCP
resources:
requests:
cpu: "3"
memory: 6Gi
volumeMounts:
- mountPath: /var/lib/postgresql
name: timescaledbdata
- mountPath: /etc/postgresql
name: timescaledb-config
volumes:
- configMap:
defaultMode: 420
name: timescaledb-config
name: timescaledb-config
volumeClaimTemplates:
- metadata:
annotations:
volume.alpha.kubernetes.io/storage-class: standard
creationTimestamp: null
name: timescaledbdata
spec:
accessModes:
- ReadWriteOnce
dataSource: null
resources:
requests:
storage: 200Gi
status:
phase: Pending下面演示了创建的临时数据库test_db在pod重新创建后丢失，在整个过程中，pod与Azure上的相同PV/磁盘相关联。
root@e70a91715239:~/keys# k get pvc -l app=timescaledb
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
timescaledbdata-timescaledb-0 Bound pvc-c7eb99cf-6a6b-11e9-b661-be660567cc75 200Gi RWO default 83d
root@e70a91715239:~/keys# k exec -ti timescaledb-0 bash
bash-4.4# psql -U postgres;
psql (9.6.13)
Type "help" for help.
postgres=# create database test_db;
CREATE DATABASE
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+------------+------------+-----------------------
postgres | postgres | UTF8 | en_US.utf8 | en_US.utf8 |
template0 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
test_db | postgres | UTF8 | en_US.utf8 | en_US.utf8 |
(4 rows)
root@e70a91715239:~/keys# k get pods | grep timescale
timescaledb-0 1/1 Running 0 12m
root@e70a91715239:~/keys# k delete pod/timescaledb-0
pod "timescaledb-0" deleted
root@e70a91715239:~/keys# k get pods | grep timescale
timescaledb-0 1/1 Running 0 14s
root@e70a91715239:~/keys# k exec -ti timescaledb-0 bash
bash-4.4# psql -U postgres
psql (9.6.13)
Type "help" for help.
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+------------+------------+-----------------------
postgres | postgres | UTF8 | en_US.utf8 | en_US.utf8 |
template0 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
(3 rows)
root@e70a91715239:~/keys# k get pvc -l app=timescaledb
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
timescaledbdata-timescaledb-0 Bound pvc-c7eb99cf-6a6b-11e9-b661-be660567cc75 200Gi RWO default 83d它可能正在按照提示重新初始化。请参阅logs。任何关于它为什么会这样做的提示。
更新1:我查看了timescale pod中的挂载，它似乎对/var/lib/postgresql和/var/lib/postgresql/data有不同的分区。我不明白为什么。
Filesystem Size Used Available Use% Mounted on
overlay 96.9G 22.1G 74.8G 23% /
tmpfs 64.0M 0 64.0M 0% /dev
tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup
/dev/sda1 96.9G 22.1G 74.8G 23% /docker-entrypoint-initdb.d
/dev/sda1 96.9G 22.1G 74.8G 23% /dev/termination-log
shm 64.0M 4.0K 64.0M 0% /dev/shm
/dev/sda1 96.9G 22.1G 74.8G 23% /etc/resolv.conf
/dev/sda1 96.9G 22.1G 74.8G 23% /etc/hostname
/dev/sda1 96.9G 22.1G 74.8G 23% /etc/hosts
/dev/sdc 196.7G 59.3M 196.7G 0% /var/lib/postgresql
/dev/sda1 96.9G 22.1G 74.8G 23% /var/lib/postgresql/data 对于下面的配置，我不了解上面的挂载是如何发生的
volumeMounts:
- mountPath: /var/lib/postgresql
name: timescaledbdata
- mountPath: /etc/postgresql
name: timescaledb-config回答 1
Stack Overflow用户
回答已采纳
发布于 2019-07-26 21:05:37
问题是在postgres:9.6 Dockerfile文件中有一个/var/lib/postgresql/data的卷声明，这导致在容器上进行额外的挂载。当我们在/var/lib/postgresql挂载卷时，这种挂载是短暂的。但是我们无法将lost+found卷挂载到/var/lib/postgresql/data，因为该卷附带了AKS子目录，而Postgres期望空目录来存储DB文件。
修复方法是在/var/lib/postgresql/data挂载卷，并告诉Postgres在/var/lib/postgresql/data下使用一个子目录来存储带有PGDATA环境变量的文件。
下面是k8s状态集配置中fix的相关部分
env:
- name: PGDATA
value: "/var/lib/postgresql/data/dbfiles"
...
volumeMounts:
- mountPath: /var/lib/postgresql/data
name: timescaledata页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/57140161
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