Cloud Storage can't manage files in production, oauth2: cannot fetch token

I'm uploading my Go project to GKE as a scratch image. Following this tutorial to deliver my service account key using a secret. My deployment is exposed by a Ingress and Google generate a trusted SSL Certificate for the application endpoint. The key has Storage Object Admin role.

On my computer the service account key works but on GKE it throws the following error and I can't upload or download files.

# UPLOAD
Post "https://storage.googleapis.com/upload/storage/v1/b/1.0.0.0/o?alt=json&name=cloud%2Ftest%-e7c7-4e9a--9a75d&prettyPrint=false&projection=full&uploadType=multipart": oauth2: cannot fetch token: Post "https://oauth2.googleapis.com/token": x509: certificate signed by unknown authority

# DOWNLOAD
Get "https://storage.googleapis.com/1.0.0.0/folder/test/4e882f59.png": oauth2: cannot fetch token: Post "https://oauth2.googleapis.com/token": x509: certificate signed by unknown authority

I also read this post, the error seems to be similar but it didn't work either using an alpine image and installing ca-certificates

SOLUTION

I was missing the update-ca-certificates command, here is my dockerfile in case it helps someone

RUN apk add --no-cache ca-certificates && update-ca-certificates

Full dockerfile

# BUILD STAGE
FROM golang:1.18.5-alpine3.16 as build

ENV CGO_ENABLED=0 \
    GOOS=linux \
    GOARCH=amd64

WORKDIR /go/src/ms-gcp

COPY . .

RUN go build cmd/ms-gcp/main.go

# PROD STAGE
FROM alpine:3.15.6

# CERT PACKAGES
RUN apk add --no-cache ca-certificates && update-ca-certificates

# TIME ZONE FOR CHILE-SANTIAGO
RUN apk update
RUN apk add tzdata
RUN cp /usr/share/zoneinfo/Chile/Continental /etc/localtime

ENV TZ America/Santiago
RUN echo "America/Santiago" >  /etc/timezone

# GLIBC
RUN apk --no-cache add ca-certificates wget && \
    wget -q -O /etc/apk/keys/sgerrand.rsa.pub https://alpine-pkgs.sgerrand.com/sgerrand.rsa.pub && \
    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.35-r0/glibc-2.35-r0.apk && \
    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.35-r0/glibc-bin-2.35-r0.apk && \
    wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.35-r0/glibc-i18n-2.35-r0.apk && \
    apk add glibc-bin-2.35-r0.apk glibc-i18n-2.35-r0.apk glibc-2.35-r0.apk

COPY ./locale.md /locale.md
RUN cat locale.md | xargs -i /usr/glibc-compat/bin/localedef -i {} -f UTF-8 {}.UTF-8

ENV LANG=cl_ES.UTF-8 \
    LANGUAGE=cl_ES.UTF-8

COPY --from=build /go/src/ms-gcp/main .

CMD ["./main"]