fix: login into the docker registry (elastic#17620)

* fix: login into the docker registry

* test: make a pull after login to test

* docs: add note to the workaround

Jenkinsfile

@@ -8,6 +8,8 @@ pipeline {
     BASE_DIR = 'src/github.com/elastic/beats'
     GOX_FLAGS = "-arch amd64"
     DOCKER_COMPOSE_VERSION = "1.21.0"
+    DOCKERELASTIC_SECRET = 'secret/observability-team/ci/docker-registry/prod'
+    DOCKER_REGISTRY = 'docker.elastic.co'
   }
   options {
     timeout(time: 2, unit: 'HOURS')
@@ -644,6 +646,9 @@ def withBeatsEnv(boolean archive, Closure body) {
   ]) {
     deleteDir()
     unstash 'source'
+    dockerLogin(secret: "${DOCKERELASTIC_SECRET}", registry: "${DOCKER_REGISTRY}")
+    // FIXME workaround untill we fix the packer cache
+    sh 'docker pull docker.elastic.co/observability-ci/database-enterprise:12.2.0.1'
     dir("${env.BASE_DIR}") {
       sh(label: "Install Go ${GO_VERSION}", script: ".ci/scripts/install-go.sh")
       sh(label: "Install docker-compose ${DOCKER_COMPOSE_VERSION}", script: ".ci/scripts/install-docker-compose.sh")