diff --git a/docs/09-bootstrapping-kubernetes-workers.md b/docs/09-bootstrapping-kubernetes-workers.md
index 76c264c..816b584 100644
--- a/docs/09-bootstrapping-kubernetes-workers.md
+++ b/docs/09-bootstrapping-kubernetes-workers.md
@@ -35,7 +35,7 @@ EOF
 
 openssl genrsa -out worker-1.key 2048
 openssl req -new -key worker-1.key -subj "/CN=system:node:worker-1/O=system:nodes" -out worker-1.csr -config openssl-worker-1.cnf
-openssl x509 -req -in worker-1.csr -CA ca.crt -CAkey ca.key -CAcreateserial  -out worker-1.crt -extensions v3_req -extfile openssl-worker-1.cnf
+openssl x509 -req -in worker-1.csr -CA ca.crt -CAkey ca.key -CAcreateserial  -out worker-1.crt -extensions v3_req -extfile openssl-worker-1.cnf -days 1000
 ```
 
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