├── logrotate.conf
├── Dockerfile
├── .travis.yml
└── README.md


/logrotate.conf:
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1 | # see "man logrotate" for details
2 | weekly
3 | rotate 4
4 | create
5 | dateext
6 | compress
7 | 
8 | include /etc/logrotate.d
9 | 


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/Dockerfile:
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 1 | FROM alpine:3.14
 2 | 
 3 | USER root
 4 | RUN apk --update add --no-cache logrotate && \
 5 |     rm -f /etc/logrotate.d/*
 6 | ADD logrotate.conf /etc/logrotate.conf
 7 | RUN chmod 0400 /etc/logrotate.conf
 8 | 
 9 | CMD ["/usr/sbin/logrotate", "-v", "-f", "--state","/tmp/logrotate.status", "/etc/logrotate.conf"]
10 | 


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/.travis.yml:
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 1 | ---
 2 | notifications:
 3 |   email:
 4 |     on_success: never
 5 |     on_failure: always
 6 | 
 7 | services:
 8 |   - docker
 9 | 
10 | env:
11 |   global:
12 |     - DOCKERHUB_USERNAME="kicm"
13 |     - IMAGE_NAME="logrotate"
14 | 
15 | jobs:
16 |   include:
17 |     - stage: build docker image
18 |       script:
19 |         - ./build.sh
20 | 


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/README.md:
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 1 | # Overview
 2 | We need a solution for legacy apps running in a kubernetes cluster writing logs to a file without rotating them (in a traditional way).
 3 | 
 4 | # Example Setup
 5 | I assume that a legacy app inside Kubernetes write logs to a PV resp. PVC called `app-logs-pv`.
 6 | 
 7 | ## Kubernetes Prereqs
 8 | The example PVC `app-logs-pv` has to be present and the legacy app writes its logfile to this. `accessMode` of this PVC must be **RWX** (ReadWriteMany) as we want to rotate them from a different Pod (seperate to the application).
 9 | ```yaml
10 | apiVersion: v1
11 | kind: PersistentVolumeClaim
12 | metadata:
13 |   name: app-logs-pv
14 | spec:
15 |   accessModes:
16 |     - ReadWriteMany
17 |   resources:
18 |     requests:
19 |       storage: 500Mi
20 | ```
21 | 
22 | ## Cronjob example setup
23 | ### Define Logrotate Config
24 | ```yaml
25 | ---
26 | apiVersion: v1
27 | kind: ConfigMap
28 | metadata:
29 |   name: logrotate-config
30 | data:
31 |   my_logs.conf: |
32 |     /var/log/app/*.log {
33 |         daily
34 |         missingok
35 |         rotate 7
36 |         compress
37 |         delaycompress
38 |         dateformat -%Y%m%d_%H%M%S
39 |         notifempty
40 |         copytruncate
41 |         su
42 |     }
43 |   my_txt_logs.conf: |
44 |     /var/log/app/*.txt {
45 |         daily
46 |         missingok
47 |         rotate 3
48 |         compress
49 |         delaycompress
50 |         dateformat -%Y%m%d_%H%M%S
51 |         notifempty
52 |         copytruncate
53 |         su
54 |     }
55 | ```
56 | ### Define Cronjob
57 | ```yaml
58 | ---
59 | apiVersion: batch/v1beta1
60 | kind: CronJob
61 | metadata:
62 |   name: app-logrotate
63 | spec:
64 |   schedule: "*/1 * * * *"
65 |   concurrencyPolicy: Forbid
66 |   jobTemplate:
67 |     spec:
68 |       template:
69 |         spec:
70 |           containers:
71 |           - name: logrotate
72 |             image: docker.io/kicm/logrotate
73 |             volumeMounts:
74 |             - name: logrotate-conf
75 |               mountPath: /etc/logrotate.d
76 |             - name: app-logs
77 |               mountPath: /var/log/app
78 |           volumes:
79 |           - name: logrotate-conf
80 |             configMap:
81 |               name: logrotate-config
82 |           - name: app-logs
83 |             persistentVolumeClaim:
84 |               claimName: app-logs-pv
85 |           restartPolicy: OnFailure
86 | ```
87 | 


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